To be honest lately I've just been using some slight room reverb from the Quad Cortex, or VST's for recordings. I don't play often with a lot of reverb, I'm more of a rhythm guy and it's so easy to lose clarity.
That being said, I've built Gravitation (which is...
fine, but nothing amazing to me) and I've got a True Spring (very good digital spring pedal), a knockoff Slö and I built the Disappearing Act spring reverb (
https://scientificguitarist.wixsite.com/home/disappearing-act). I probably like the True Spring the most, but the Disappearing Act is nice too - it can be a little noisy if you want it as wet as it goes, unless you cut the top end, though. As far as DIY spring reverbs go I'd say it's probably the easiest and simplest, but that's just my opinion. Oh and a Space is Fun which is the Reverberation Machine - it can be quite cool, but it's sort of a shit design IMO overall, and IMO you can't just toggle it on and off since it colors the dry sound so much too.
All in all, I'd maybe suggest to go commercial unless you really want a DIY solution. For those I'd avoid the Belton brick ones, I haven't build any FV-1 ones yet so can't comment, but if you can pull a tube spring reverb build off it would be quite cool (and you can, I'm sure, just not something I'd suggest for beginners). The Disappearing Act is probably easier, and the nice thing there is that the spring tank is the most expensive part so if the tube spring also can use the same tank you could try out both.