If time is not an issue RBA, RDA and RTA clones are inexpensive from Fasttech (directly from china) -3-4 weeks typical for my deliveries.
Clones that have performed well for me include: IGO-L, IGO-S, Kayfun/kayfun Lite.
VV/VW devices are the only types I presently own and all Innokin brand - all vv/vw devices.
MVP 2 - $40ish and a great workhorse of mine. For out and about/stealth their itaste V3.
Just because - I also have their EP, SVD and 134. All are performing great - only heard of bad reviews from some with SVD (fire button) and 134 turning itself off sometimes.
Their are dedicated threads for the MVP 2 and V3 for many other persons comments on these models.
Faster and the same price to just buy Innokin devices on ebay usually.