We've gone for a hammock (yet to use it!) based on what friends have said about babies growing out of bassinets in no time. Even tho hammocks tend to only be used til about 8-10 months most people I've spoken to have raved about them (epsecially for collicky, reflux babies) and if by chance your baby doesn't take to it they are sooooo in demand you'll sell it on no worries
Apparently the curve once you've inserted the mattress is minimal and many chiroparctors actually recommend hammocks over cots....

Good luck with your decision!