Sounds to me like you just have something personal against gas piston AR15's. I think piston AR's are the way to go when shooting AR's suppressed.
Wait. Regulating the gas (by venting excess gas into the atmosphere) with the Switchblock is "better" than doing the same thing with an external gas piston system?
What is so great about regulating gas in a D.I.? Same gas gets piped directly into the bolt. It gets just as dirty as unregulated gas. At least with the piston, it isn't baked on the bolt.
Pistons may affect follow-up shots if any, but how does it affect accuracy? And before you start on barrel harmonics, the Osprey system uses the standard FSB and has no anchored contact with the barrel to the receiver.
Parts interchangeability is about as retarded as asking what other company besides Noveske makes parts for the Switchblock.
That's OK. Sounds to me like you're trying to justify a small company's piston retrofit as a replacement for a military proven design. I have shot both piston AR and DI suppressed with the same barrel lengths and suppressors, I can't say one was any better really.
My point is that no, DI isn't perfect. But if you have a gun that runs unsuppressed and put a can on it, it's now way over gassed. Whether you limit the gas by means of a switch block, smaller port, or other adjustment method, you need to look at the ideal set ups if you are going to compare. Comparing an overgassed DI to overgassed piston will at least initially favor piston, it's the long term I am interested in. Ideally, I would prefer a properly gassed DI to any piston any day, if I didn't have a properly gassed DI I would consider Piston.
Your comments on the switchblock don't make any sense to me. What is going to happen to the gas block to make it need parts? It's a pretty low maintenance part, under almost no real stress. What about if your op rod, carrier, piston or piston chamber break? Can you get a spare part from any other AR out there? I think commonality is a large issue when looking at moving parts that can actually fail. Worst case if a switchblock were to fail, any gas block could replace it.
Piston has a LOT of faults from carrier tilt, non-common parts, a million competing proprietary designs, louder, less accurate, more parts to fail, but yes, it IS cleaner in the receiver (although not in the chamber or gas block). Funny that, I haven't cleaned my AR in 2000 rounds or so, no problems so far and it's a wylde chamber. I should clean it more often I guess, but I don't see the need yet.
Feel free to run your Osprey piston set up, it looks decent, and I hope if it ever breaks the parts are readily available. I'm going to run DI because that's how the gun was designed and it seems to work fine for me. If I was going to run a piston system I am certain it would be in a complete system that was designed for it (HK, LWRC, POF, etc). I would also choose a system that was set up to have a suppressed setting. But to each his own.