HotDan!
Friend of Leo's
All my amps are tweed and have no built-in reverb, so I need pedals for that.
I've been through a few in my search (trying to achieve the classic Fender reverb sound). To my ears, the Strymon Flint is the closest I've found to nailing an actual Fender reverb, with the added bonus of three iconic tremolos: round wave (Vibroverb), square wave (any black face Fender combo), and a Magnatone-like tremolo/vibrato pattern.
The best reverb unit I've played through was a friends early 60's Fender tube reverb. Absolutely glorious sound, but pedals are much more practical.
I mostly play through Fender amps and the onboard reverbs are fine. For those amps that I may play that either don't have them or have crappy ones, I use a Wampler faux Spring Reverb. There may be better ones out there but this one works well for me...