There are lots of places to get the supplies, I normally go with okcvapes because they are close to me. You can get the wire off of Evilbay in bulk easily, the mesh is a bit harder, but a 12x12" sheet will make a LOT of wicks and I hear of people using the same wick for 6mos to a year!
The AGA-T I have, yes, it's that finicky! They seem to be notorious for that! Tighten the nuts too much, it freaks out, get it too far from the center connector, it freaks out. Etc..... I don't know how many travel out and about with them, that's actually a thread I plan to start tonight in the RBA section. I don't know anything about the ZAP, it's out of my reach right now, although I plan to get one sometime in the future and I hear it's much easier to work with.
I also have a Trivveca (Rainbow) dripping RBA, this thing is simple as simple and hits like a mother bear! I love it! BUT, I took it with me to the convince store last night in my shirt pocket. When I tried to hit it, dry as a bone! I got home and looked in the mirror, juice stain on my shirt! It had leaked out all the juice!
Just like everything else in vaping, you have to find what works for you and what doesn't. I like the RBA factor that I can, if I have to, get what I need to rebuild it local. And I'm not stuck at the dependency of a vendor to get what I want/like in stock!