We bought a simple one that was on special (and I love it - we use it heaps, particularly in the early days for DD's day sleeps), but then a few weeks after buying it I saw one with the attachments for the same price! Sometimes I thought it would have been super having the bassinette attachment because I used to pat DD to sleep and that involved bending over the cot for a while! Having her higher up would've made life a little easier on my back, methinks
Having said that, we did do ok without them and now they'd just be something else I'd have to find a storage space for.
In any case, keep an eye out for specials! Sometimes you can get a really good deal.