Socrative is still a wonderful tool for the classroom (especially considering that it's free) but, after using it a few more times I'm running into some problems that I need to make you aware of and that I've already alerted the app producer too.
In using it I allowed students to use their smart phones and the iPads I have in the classroom. The students using the iPads had virtually no issues, but those that were using their smartphones encountered some issues that prevented the experience from being positive. One, when viewing an activity on Socrative on their smart phones they often had to scroll up and down to see all of the questions and answer choices, and too often as they scrolled the program interpreted the scrolling as an answer selection. I contacted the app maker to suggest adding an "Are You Sure?" response to answering the question to avoid this.
The other issue that happened more with smart phone users than laptop and iPad users was questions already answered would reappear. I also alerted the app maker to this bug as well.
Considering both of these issues I've decided to only use Socrative when either all my students have an iPad in their hands or if they're working on something else and can pass the iPads I have in the room around to each other.
If you're in a one-to-one iPad classroom, then you shouldn't have very many troubles at all.