It would be ok to lose signups from people who would not ever buy your product, but I don't think that's the case.
I for one, subscribe to a lot of SaaS but would never put in my CC number just for a trial.
And what about corporate customers? I think many subscribers can come from corporations where someone somewhere tried the product and liked it, and then made sure his company paid for it. If he had to enter his CC# before he could even try he would probably not do it.
I think the target population matters. If you're selling to teachers or dentists, then you should speak to teachers or dentists to learn what they will do or not do.
If you're offering a jQuery framework, then HN seems pretty relevant as far as the people susceptible to subscribe to your services.
I was thinking that I would be reluctant too, but then I realised that I have given plenty of SaaS companys my CC up front - sometimes not even for a free trial (but usually with a moneyback guarantee). E.g Linode and JungleDisk.
I for one, subscribe to a lot of SaaS but would never put in my CC number just for a trial.
And what about corporate customers? I think many subscribers can come from corporations where someone somewhere tried the product and liked it, and then made sure his company paid for it. If he had to enter his CC# before he could even try he would probably not do it.