i havent tried many different ones, but i watched several videos where people talked about that on youtube... i got a brazilian style i would say single hammock although it was advertised double but the same size (200x135cm fabric surface) is usually advertised as single. i would not recommend a smaller one in any case, that one is just the minimum to be exactly right for one person in my opinion. as i didnt have much funds and have no good wall to put it up, when i got it, i decided upon one of these "vivere" hammocks with a stand, that are also available on amazon (but i purchased it via a local hardware store).
what i would not recommend is a hammock that has planks on both ends to make the fabric flat, you definitely want a south american style one that folds in on itself so you can optimally stretch it out with your body weight and shift into a comfortable position. also, you do not want one that is made out of a wide fishnet fabric, for obvious reasons i guess, unless you want to wake up looking like... well i have seen sausages that look that way. also, the material should be 100% cotton, preferably organic, otherwise the switch doesnt make much sense... there are a lot of nylon, polyester and polyamide cotton blends on the market from what i saw.