Best fan is like getting asked what's the best vacuum....... The one that gets used is always my answer..
I recently got 2 new Dri-pods, which work decently well.. I also have 7 air paths, 1 drieaz Velo, 1 drier stealth.. Dri-pods are quieter and get less noise complaints.. Even those miniature snail fans are pretty nice on price and noise..
I assume you'd be using it only while your on the job and not leaving it behind to pickup later?