The jet suits are amazing, we no longer have to build space ladders.

[Gurgel]

I don't use them. No need and normally-suited dupes are faster.

[Fen1kz]

I've heard they lag. And personally I tend to believe it, I experience heavy lagging when my 3 dupes fly around my Rocket Construction Site

[Nitroturtle]

I have them setup to allow access to my rocket silo and area around my bunker door layer to collect regolith and iron.  This area is limited to only jet-suit dupes, with the exception of my two astronauts who can pass without jet-suits and only without as they have their own route to board their rockets.  Limiting the area accessible by the jet-suits allows me to use them without causing the crazy amount of lag others are experiencing.  In fact, my game lagged horribly while getting the area setup and restricted, because dupes would find their way into the main base with their jet-suits on.  Once I had them locked down to a smaller area, it was light night and day with regards to the lag.

[Sasza22]

I use them to make space construction cleaner. No randomly damaged ladders etc. Once the construction in space is over i disable access and realy on normal atmo suits to reduce lag and save petroleum (and dupes from getting stuck i random spots).

[Nativel]

As for me lag suits works bad, dubs flying too slow and they just lost on those surface Iron sweeping.