for years i used bivy shelters or bivy sacks both for easy of pitching and often "real estate" is at a premium and finding space for a larger, more mainstream floored shelter could be just a little difficult at times.
tried an original floorless HS Squall with groundsheet. much easier to find a spot to pitch it than a floored shelter, but it proved sub-optimal if heavy rains were expected that weekend. the amount of water we can get at times can easily overwhelm a groundsheet and the largest "LNT" rain trenches i care to dig with a Montbell Ti potty trowel. in these conditions, only a bathtub floor suffices. now, the real-estate issue surfaces again, depending upon where i attempt to bivouac.
it's a trade-off. how much rain do you expect to see when on a trek is the question i suggest that you ask yourself. the answer to this question, IMHO, together with how easy is it to find adequate real-estate to pitch a floored shelter, will govern your choice of floored vs. floorless shelter.
The floorless, original HS Squall did a fine job when it came to bugs in my limited experience with it. due to the aforementioned heavy rain issue, i gave it away and purchased, immediately after their introduction, a GG Squall Classic (spinnaker and floored), but haven't had a chance to use it yet, so i can't comment on it, other than to say that i already know in some places i'll have problems finding sufficient real-estate to pitch it. i have a SMD Lunar Solo 'e', and sometimes have trouble finding sufficient even surface to pitch it.