i have a 16g currently and had a 39 on before that. the vf39 felt faster. it also felt like it drove better. this could be for many reasons though.
1. when driving with the 39 i was using stock boost control with vac lines that didnt fit snug over the the nipples. and thusly i was always driving around at 14 psi with spikes higher.
2. the leaking boost control lines also caused a part throtle full boost condition that was verry interesting. at 70 mph and 10 inhg vac adding a little throtle it would hit 14psi verry easy and the car would pull nicely to 100 without downshifting. causing the turbo to feel more driveable.
when using the 16g with the stock boost control i was hitting well stock boost at 11 psi. it didnt feel as fast problay because it wasnt the same amount of boost yet some friends i took around said at stock boost the 16g felt faster than teh 39 at 14psi. since getting the turbo i put on a turbosmart 2 stage mbc running 10 psi and 15 psi. i dont verry offten run 15psi because of fear of leaning out as a fellow with i similar setup to mine (i have a larger and front mounted intercooler) was getting pretty lean on the dyno and he has a 255 fp and i do not. i still get ptfb but it doesnt pull the car as well as the 39 did in this condition. infact it doesnt pull much at all. instead i am forced to coax the car into downshifting by punching the gas down (4eat) and then it pulls nicely. another friend of mine who has a 97 prelude took a ride in my car at 15 psi and he says that its incredibly fast even though i dont think that it is. before when i drove his car it was the fastest thing i had driven and i was really impressed with it. at that time i was loosing to his car when racing and was running 17.3xx. i havent taken the car to the track after the new turbo but i can put 4 car lengts on him in before reaching 40 mph from a dig at 10psi.
i was told by deadbolt that the 39 would have more top end than the 16g but that the 16g would have a better midrange. if you look at the compressor maps and stats in the huge thread that has the charting of the flow in cfm of many of the turbos that are popular youll see that at all times the 16g flows more than the vfx series by over 100 cfm and that includes the ever popular vf22.
in the end its your choice but the 16g is the better choice because its easily serviced rebuilt and upgradable. unlike ihi's which have been said to be impossible to rebuild and upgrade.