As far as accuracy and ruggedness, I have to vote for the 629-6. I've done better with those in IHMSA competition over the past 20+ years than any of my supposedly superior "no dash"s, -1, -3s (early and late, including a couple of DXs), or -4. If you want visual appeal, then the -6 isn't top of the heap. The ONLY reason I keep my basic 6" -1 is because it's "purty"!
I can't remember which dash versions all of my PC 629s are, but most are -6s. But plain ones are what gets used the most.