Love my 3.1L in my 92" Cutlass Supreme, she has 222k on it and is smooth as ever. Gets great city/hwy mpg and has a nice growl with the dual exhausts. This was my 3rd 3.1L and once you fix the LIM around 120k initially it has not been an issue since, plus it's a very easy fix. 2 teenage boys had not killed it or my 91' Cutlass either very reliable.
The 60 degree V6 (2.8/3.1/3.4) is a true workhorse. Solid, smooth, efficient engines. Couple problems plagued them unfortunately in the later models, specifically the distributor O-ring would leak oil and the reputation-killing LIM gasket issues. If they survive the LIM gasket (and fixed with updated part) they're pretty bulletproof.