To put the question up front: for those of you who have invested into multiple dive "kits," particularly folks diving doubles, with stages, OC bailout for CCR folks, etc. or even those of you who switch back and forth between single tank rigs and doubles, how do you select your next set of regs, and how heavily do you invest into one make/model?
Back to the OP: My first regs, purchased in the late 1980's and early 1990's, were Scubapro (Mk 10 + Balanced Adjustable initially; then Mk 10 + G250 when I needed to run two full regulators simultaneously; then a couple of more Scubapro reg items later). Scubapro's reputation was very solid, so I made the decision to invest in Scubapro gear from the very start. ("Buy once, cry once.") I was very lucky to have been given sound advice by people I trusted.
I would have been perfectly happy to own only Scubapro regs, but I moved to the Great Lakes area and began diving deep shipwrecks (in the mid-1990's, in Lakes Huron, Michigan, and Superior) in very cold water, using liberally pumped, HP tanks. The very experienced divers I was diving with swore by Poseidon regs for this type of diving, so my next regulator purchases were a couple of Poseidon Odins to use with back-mounted doubles. That is, my decision to invest in regulators completely different from the Scubapro regs I had already invested in, was due only to the new diving venue. If I had pursued deep diving in the Caribbean (using Al cylinders), say, instead of in the Great Lakes, I am almost certain I would not have invested in my Poseidons.
My Scubapros served the role of bailout/deco regs--so, they continued to be used and never were neglected.
By the way, I no longer (not since the early 2000's) do deep, Great Lakes diving. So, I typically use my Scubapros now for my open water, solo, recreational dives in temperate (Missouri and Arkansas) fresh water--when I am not using my VDH-upgraded U.S. Divers DA Aqua Master double hose regulator, that is.
I hope this helps.
rx7diver