Welcome and good to see you posting!
Dont know anything about San Marino other than the name and that CoffeeParts have some spares (a good sign as they keep them in stock and at a good price).
The BZ35 is an excellent machine. Some (non plumbed in) versions were made with vibe pumps..... if you have a tank, it is hard to fit a normal rotary pump because of its size- so many manufacturers (Bezzera included) fitted the much smaller vibe pump to these machines.
I think Id go for the BZ..... they have an excellent reputation and several members have BZ machines (but without knowing the relative price being asked, condition etc - its just a guess)