Tanks I have had zero issues with.
Kangertech Mini Tank with stock coils. When RBA section you have to build it right, but have gotten to the point of no leaks
30 watts generally on stock coils, 15 watts on RBA builds currently.
Aspire Atlantis V2 - Stock coils works fantastic, never had ANY leaks with heavier VG based juices. Now I have noticed it will spit/drizzle with thinner juices, but if you like foggin' it, 30/70 and up don't leak and it wicks very well. I usually run it around 30w for my speed.
Aspire Triton - Stock coils work fantastic as with the Atlantis (same coils) Only difference I noted was the flavor is muted. RBA section is OK. Flavor is better, but for a rebuildable IMO it's not great, just good.
Obviously my opinion may not be like others, but maybe this will help
Good luck to you.