I recommend that you buy what brings you the most happiness: some are happy to shoot their MGs, some are happy to own and occasionally shoot a MG that brings back a strong memory of a time period or friend, others are happy to create their own personal museum that they curate with what they believe are the best available versions of MGs, and still other are happy to use their MGs as a hedge against inflation or a potential investment.
For me, I only own three MGs: the first I bought was a M2HB as I always wanted one and I have many other Browning designed firearms, the second was a M11/9 that I purchased so that my family and friends would be exposed to the most variety in a MG at the lowest cost point as I have a lage upper in 22LR, 9mm, and 5.56, the last one was an UZI bolt gun that I purchased because it was an iconic MG and I won it at an action for under $10k with a UZI model B host.
As to shooting them, I personally enjoy shooting the UZI suppressed the most, however when I go shooting the M11/9 is always the most popular among others. The M2HB I enjoy shooting but it takes a lot more planning and preparation to take out and thus sees less trigger time.
I believe MGs will continue to hold value as there does not seem to be any likelihood of allowing more transferable MGs to be added to the registry in the current political climate. However, I am cautious about paying too much for some collectible MGs as I question if the market will still be there in the future. As an example with the boomer generation aging out I expect the hot rod/classic car market will experience a price correction as younger generations do not share the same affinity or attraction to that style of automobile (ie. a little due coupe). I suspect the same will happen eventually with the high end priced Thompson, grease gun, and MP40 market.