Whoever says that it is too hard must be an idiot; it may take too long, but as for being difficult, all you have to do is read e-mails. If anything, FC is harder since they have a time-limit of 180 days from the time an offer credits to the time you request payment. However, I agree that I like FC much better; even though the threshold is comparable ($30 compared to $25, so not much more for Inbox Dollars) and they're both fairly easy to earn money, it takes a shorter amount of time to reach $30 with FC than it does with Inbox just by doing the free stuff. FC has all of the different bonuses that you can get (post your payments, forum bonus, game bonus, Tues. / Sat. bonus, etc), plus the PTC is worth quite a bit (usually more than what I'd get from Inbox each day by just reading e-mails and doing their videos).
As for the $3 fee, you do get it credited back. I knew that if you wait till you reach $40 then it is waived, but when I cashed out my $30, it said you needed to reach $40 in 30 days, which considering I only did the e-mails (they didn't have the videos at the time), I decided that there was no chance for me to complete the extra $10 in 30 days, so I just accepted the $3 fee. I didn't think about waiting till you were very close to $40 before cashing out; I guess I just though it was always an extra $10 that they tried to get you to earn in 30 days (which would only be possible by completing non-email offers), and not that the $40 threshold was a fixed amount. Although if they don't give you a $3 bonus if you cash out at $40 (where your fee got waived), then it'll take even longer the next time to cashout. I think for myself, I'll keep cashing out at $30, accepting the fee, and if I even decide to quit, I'd wait and cashout the $40 to prevent the fee.