I am not sure what Larry's issues could be, but locally, the Mk 16 has performed extremely well. My most frequent dive buddy has used his extensively over the last couple years doing about 130 divers per year, nearly all in cold water (bottom temps in the 40's) and with a large percentage of the dives being to 130 feet or deeper. It is also the reg used by the local dive rescue team and by several local divers. We have had zero complaints or failures with it.
The Mk 17 shares much of the general Mk 16 design, but based on expereince with the Mk 16 has been refined in several areas, including the fully sealed diaphragm and a newly designed high pressure seat guide. Scubapro has put an extensive amount of design effort into it with the goal of creating an optimum, no compromises diaphragm first stage design and I have no doubt it will prove to be even more reliable than the Mk 16.
Larry is mistaken in his assertion that SP is "selling" the Mk 16 to TUSA or that TUSA is marketing the Mk 16 as one of their low end regulators.
Scubapro designs regulators but does not waste money on production facilites for what would be relatively low volume production runs. Tabata has manufactured Scubapro's designs under contract to SP's design and quality specifications for decades. Historically, license agreements are negotiated where once SP's exclusive rights expire, Tabata markets internally identical but cosmetically different versions of SP regulators through TUSA - which is the acronym for "Tabata USA". To my knowledge this has been occuring since the Scubapro balanced piston Mk 5 first stage, which was also marketed by TUSA as the TR-400 for at least a decade after SP discontinued the Mk 5.
The current TUSA R400 balanced diaphragm first stage is identical to the Mk 16 with the exception of the trim boot on the ambient chamber end of the regulator. It is marketed in their R460 package and is in my estimation an upper end TUSA regulator rather than a low end regulator.
Scubapro has discontinued the Mk 16 in the US on July 25th. Scubapro has historically allowed US dealers to depart from the dealer pricing restrictions on clearence items and in a market where the margin runs around 100%, the savings can be considerable. I have gotten great deals on BC's regulators and wet suits on clearence in the past (one of my MK 20 D400's was bought for $340 - 10% over dealer cost - after it had been discontinued.) I don't expect that Scubapro would treat the Mk 16 any differently, so if dealers choose to do so, they could offer some very competitive deals on them. Some dealers will stock up on clearnece items to provide them with potential sale items to complete with on-line retailers and cheaper scuba gear companies in general while others don't, so your mileage may vary.
US Scubapro dealers are restricted from selling Scubapro regs on-line or by mail. The customer has to come into the shop at some point in the transaction for the sale to comply with the dealer agreement.
So if you buy one on-line, it will be a grey market reg sold without the Scubapro US warranty and free parts for life program. However a discontinued reg bought from an authorized dealer in a shop at a clearence price would still be sold with a full warranty and the parts program. So for the same price as a grey market on-line reg you could probably get the same reg for the same price but with a warranty through an authorized dealer.