well i got a 90ex, main purpose is to pair with 430ex II. I use it with my 6D.
I am an amateur, so i don't observe the recycling time. But should be fast, maybe a second or 2. i dont know.
I use 90ex as fill flash, catch light to subjects face or eyes.. or when the background is bright, need to expose on background and fill flash the foreground. I don't intend the 90ex to light the whole scene, with 6D i can increase ISO to like 10000 and would still be good. So the power is OK, after all point and shoot got smaller flash and can do its thing, what more 90ex, a bit bigger.
Also i dont use telephoto, i believed 5meters away, 90ex fill flash still can do the job.