I spotted issues with the signup process yesterday, the guys have done a good job of chatting to me on twitter to try and resolve the issue, so thumbs up.
On a separate note, I agree with the comments about the per day pricing. It is a little confusing and I would rather just see a monthly subscription cost, with a few plan variants based on # of projects and users. Your making me think to hard about paying for something when I have to start calculating how much it will cost me. You should definitely consider simplifying it.
I disagree with the comments around pricing though. I think that estimated cost is well worth not having hassle, and when you consider it to the cost of say your mobile phone bill. Just ask which do you use the most, more importantly which one is making you the money in the first place.
If I'm honest I think the pricing is a on the low side, However I wouldn't limit the free plan to "open-source" projects either. Depending on how you are quantifying open source. If you require a public github repo then I would potentially suggest it's a bad thing. People need chance to use your IDE for a project to see if they are willing to pay. Allowing only say one or two projects makes more sense I think.