I evaluated a lot of helicopters before I bought my R22, including the UH12C. Yes, it does in fact have five time-lifed parts; a surprising number that you'd expect to be time-lifed are on condition - including the blades, which are balsa wood aft of the spar! It's a shaky old cow to fly, and it's an old design with all the concomitant maintenance problems. But the killer was the Vne. 75 miles an hour - not even knots. Comfortable cruise is about 60mph, which is fine if you don't want to go anywhere.
The 12 is a 1940s design; if you'd be happy buying a 1940s car, go ahead and buy one, but if you'd rather have the year 2000 model, go for the Robinson.
I also spoke to a number of Enstom owners.