I have flown a couple.
I concur that they are snug once you are in, and you need to be double jointed to fit in one.
Negatives
Visibility upwards is zero
controls sloppy
general speed slow
fuel capacity limited
most are underpowered
VW powered ones can be a pain to start by hand
no two are alike..........
build quality varies immensely
Can be interesting in a crosswind
Positives
They are great fun
Cheap to use and run
They are great fun
Generate conversation wherever you go
They are great fun
Easy to hangar (small wingspan)
They are great fun
I'd probably buy one.............. if it was in good nick
Arc