I also have a TMD22 turbo that is getting a bit long in the tooth (1995, 8000 hours). It still runs great and gives me no trouble, but I have always had a look out for a potential replacement. So you might benefit from my
research.
As other people here have mentioned, the Betamarine is a first class engine. They have good
service and I really like skipping the
maintenance and fragility of the turbocharger.
BUT... and there is always a but with boats... Swapping out the nominal 75 HP TMD22 (550 lbs) for the nominal 75 HP Beta75 Betamarine (911 lbs) will add almost FOUR HUNDRED POUNDS to your drive train weight. That is the weight penalty from skipping the turbocharger. Ouch. At least on my boat, I am not ready to pay that
price. That might be a price some people would be fine with, it's just a judgement call that depends on your boat and lots of other factors.
Interestingly, the Beta85 at 790 lbs weighs LESS than the Beta75... because it has a turbocharger. So that might be an option if you're fine with the turbo.
I have no experience with the Volvo D2, but I do know many people with D3's. Based on their collective experience, I would not take one if it was given to me for free.
I have never heard serious complaints about the Yanmar engines in this size range. If I had to swap today, I'd go with the 75HP Yanamr while it is turbocharged, it is also NOT a common rail engine, and weighs even less than the old TMD22