This is great, look forward to reading the second part. At first, the price seems expensive, but when I think about it, it's really not. You are offering a lot of functionality when it comes to scheduling tweets and that's a feature people will find super useful (unfortunately a lot of those people may be spammers, but at the end of the day as far as your concerned, your business is your business and theirs is theirs…
I'm not a huge advocate of freemium and I would not suggest lowering the price, however you may want to extend the free trial period a little longer. Thanks for the positive feedback :) Regarding the free trial, I'm kinda hesitant, as if you can't decide after 10 days, will another 10 really make that much of a difference? That said - I accept I could be wrong ;) How long do you think would be fair?
FWIW, Basecamp offers a 30 day free trial for their services.