This is not a topic I can claim to know anything about (though I would be interested to learn more if anyone else cares to enlighten me). My gut reaction to it however, and to the subject of "speciality" disabled dating of any sort, is to feel wary, and not a little cynical. It seems to me that there are probably better ways of achieving the same ends as you would be hoping to by finding such a site (though I can see the potential appeal for people who feel that they've had relationship failures due to their condition, or that it "stops me getting a date").
To begin with, in the context of finding "serious" relationships, I think most people who are likely to actually be worth having are not going to be so badly discouraged by health issues such as epilepsy. Those who are, and especially those for whom it would be the primary reason for not wanting to get involved, are very likely to be people you would be better off without for other reasons in any case. It doesn't bode well for their capacity to deal with difficulties, including health problems for either partner, that may come up later in life (and probably will for most people). Conversely, if someone is not too fazed by knowing about health issues beforehand and shows a willingness to adapt, this is likely to indicate that they are a strong person who posesses the capacity to take life as it comes and deal with issues as they arise, rather than getting easily flustered when things are not "perfect". I think this is the kind of person most of us want in the end.
Of course, disabilities and serious health problems in general, and particularly epilepsy with its tendency to have a negative social impact (at least when dealing with people who are not educated on it) probably do have more of an impact on short term/casual dating than more serious relationships (all other things being equal) and I think it's only reasonable to agknowledge this. I can quite quite see that if someone is at present mainly interested in dating on a casual basis or the relationship hasn't developed very far (and their level of interest is at present uncertain) they are not going, in many cases, to want to deal with the fear and uncertainty, and potential embarrassment, of dealing with someone who has this strange condition that they probably don't understand, and in many cases are not going to want to learn more about. I do think though, that this may have more to do with the very uncommitted nature of casual or early stage dating, and the lack of investment that many people who participate are willing to put into any one person, than your epilepsy.
On the other side of things, though as I said I can see why it may be tempting to want to join a site specifically targetted towards finding dates for disability sufferers in general or those who have epilepsy in particular (surely, one might think, I would be guaranteed to get some "action" here if anywhere?) it doesn't seem to me something that stands up well to closer scrutiny.
I think it's very important to ask: why are other people on the site? Are they joining because they have a disability themselves, and want to meet others just like them? Or because they want to pursue relationships with those who have disabilities, or perhaps a specific condition such as epilepsy?
In the first instance, it would be good to remember that while it may be tempting for people with similar disabilites to be drawn to each other due to the mutual understanding that is naturally hoped for (in contrast to the incomprehension that might be expected from most people), the posession of a particular healh condition is not actually a terribly sound basis for a relationship. A couple really needs to have more than that in common for any deeper level of compatibility to be present that will sustain the relationship past the initial stage of excitement at meeting someone who knows what you're going through at last. Unless you allow your disability to define who you are as a person, of course, which I sincerely hope is not the case. There is also the danger of low self esteem being a factor in causing you to seek this kind of relationship, the subconscious fear that somehow a "normal" person will not percieve you as being good enough for them, and so you will have better luck with one of your "own kind". I don't think it's healthy for anyone to subconsciously devalue either themselves or their potential partners in that way, and can see it being a potential issue in any kind of "disability" based dating.
In the second case, it perplexes me a bit that someone without disabilities themselves would specifically seek out those who did for relationships. If they are interested in disabled people, or people with a disability, by preference, it could perhaps indicate that they are an unusually caring and selfless person. Or, it could indicate that they are domineering individuals who want to control and/or abuse their partners, and see those with disabilities as a vulnerable, and perhaps desparate demographic that they can exploit. Or it could be because they have very low self esteem themselves due to psychological issues (not a deal breaker in itself perhaps, but such people can be difficult to sustain healthy relationships with and it raises similar issues of potential devaluation to when disabled people seek others for low self-esteem reasons). They could also enjoy the feeling of power over someone they see as vulnerable and needy without having specifically abusive or controlling intent (might suit someone who doesn't mind being a somewhat submissive partner, but not others). Or perhaps they have an actual fetish, and are sexually or emotionally excited by the characteristics. physical signs, or medical paraphernalia of a particular condition (I personally have no wish to be objectified in this way, and I doubt many people reading do either!).
Most of these reasons are enough to give one pause for thought, at the very least. Would you really want to have a relationship with someone who was interested in dating you for most of the reasons I've suggested above; or would you want to become involved with someone for these reasons, or because they were attracted to and valued you as a person independent of your condition? I think there are inevitably going to be a large proportion of people on "disability dating" sites who have underlying motivations similar to those I've suggested; and personally I'm very doubtful that the benefits of getting involved (which are essentially, of finding someone who is not going to find your epilepsy/other health condition a deal breaker) are worth the very high risk of meeting people who are likely to have issues of their own that are far more problematic.
Edit: If anyone has had good experiences with this sort of thing, by the way, I'd be interested to hear about them. I don't want to put a downer on the prospect of people increasing their dating and relationship chances: but I AM concerned about whether people are properly valuing themselves and others as potential partners, and really giving themselves the best possible opportunity to find someone suitable.