halocline
Contributor
I spoke to my local dive center and they recommend rather than spend money on servicing the Apeks, I should sell the Cressi and Scubapro stuff and use the money to buy a Poseidon First stage and octopus to go with the Poseidon Second stage I already have,
Let me take a wild guess...that shop sells poseidon, right?
Nice to know that the U.S. doesn't have a monopoly on slimy dive shops.
Any of the regs that you have will almost certainly work fine, assuming they're in decent shape. The only stuff that I'm quite familiar with is the scubapro MK16, and as I said before, it's an excellent first stage. What you need to do is find someone that really knows about regulators that's not trying to sell you anything, to evaluate what you have and advise accordingly. I certainly know that a used G250 or D400 2nd stage paired with the MK16 and your R190 as an octo would be an excellent set up, and would probably cost about $100 or less. But its likely you already have everything you need.
Regarding servicing the apeks, if your friend has agreed to loan you long-term his nice regulator, it seems to me getting it serviced would be a nice gesture of friendship, hardly a waste of money. Use it for a season or two and by then maybe you'll have gotten to know someone who can really help you put together a nice reg set.
The poseidon regulators have their following, especially in Europe, but they are typically somewhat specialized to work on, which can present a convenience problem. I personally avoid them for that reason. But that's just personal opinion, not any slam on poseidon.