I first bought these shifters to put on a 20-year-old Bike Friday that has an old Shimano road rear derailleur and a six-speed freewheel on a 3-speed Rohloff rear hub (equivalent of a triple crank and a six speed cassette). I recently bought another set to replace 12-year-old SRAM Apex integrated shifters on a Novarra Veritas lightweight touring bike with a double-ring crankset and a 10-speed rear cassette. Here's my report out given the combined experience on both bikes:
1. The left shifter definitely works with the three speed hub and so, presumably, would work fine with a triple crank.
2. The right shifter works with both the six-speed freewheel and the SRAM 10-speed cassette. It can shift cleanly to all 10 cogs.
3. It takes some effort to shift the SRAM front derailleur with these shifters, but it also took more effort with the original SRAM integrated shifters so no complaints there.
4. The black plastic bushings on the retaining nut side of the Dia-Compe assemblies have held up OK but I wish they were made of metal. Be careful when installing, they have a raised tenon that engages the rectangular hole in the shifter and that tenon is pretty fragile, you can crush the corners if you aren't careful to fit it exactly into the rectangular hole during assembly.
5. Having done multi hour rides with these, I notice that after a while the retaining nuts loosen. Having grown up in the era of the original friction shifters (I had both Suntour and Campi) I recall that this is why the retaining nuts have the triangular pivoting grip rather than a slotted, hex, or phillips head that requires a tool...you can tighten while riding. Still, it's a bit inconvenient to have to tighten while riding--my old Suntour downtube shifters, which I still miss, never had to be tightened during a ride so this is a minus on the Dia Compes.
If the bushings were more durable and the shifters didn't require tightening at fairly frequent intervals, I would give these a five. I see other posts talking about threadlocker so the loosening issue isn't just me, but I rode those Suntours forty years ago and they didn't have this problem, so it's fair to expect a better solution from Dia Compe. For the price I think it's fair to expect that and the bushing to have been better addressed by the manufacturer. For comparison, a set of these plus Tektro brake levers is only $60 less than a set of brand-new SRAM 10-speed integrated shifter.
In summary, they get a four of five for their durability (they're bomb-proof except for that plastic bushing), ease of installation, ease of maintenance, and the fact that they'll likely work with any cogset from 10 speed back through the freewheel era. They get a point off for the cheap bushing and their loosening habit.