I have owned and worked on a number of 45's from a number of manufacturers, including an old one made in Argentine under Colt patent. What makes the Model 70 Colts desirable, in many people's minds, is the lack the firing pin block (think S&W Revolver lock here in terms of the amount of love given this feature), the lack of which enables even average smiths to get remarkable trigger pulls. Good to great smiths however can match, or come darn close on most Series 80 guns, it just takes more work. And much like the S&W lock, the firing pin block can be disabled, as in removed, but very few smiths will do it because unlike the S&W lock, removal does constitute a safety issue when the gun is being carried or in use.
But I digress. Any 45 with a good barrel and repeatable lock up will likely out shoot the shooter. The other end of the equation though is feeding and ejecting. The Gold cup of old was limited to ball ammo, in this respect. That's not to say you couldn't use semi cutters or hollow points in them, just that they were not designed with those bullet configurations in mind and often required modifications to make feeding reliable. This is the point where some Gold Cup owner will pipe up and say "Mine always shot anything I fed it." That's nice, but you were lucky. One of the problems of 45 feeding was/is different designs where the feeding ramp is incorporated with the barrel, vs. the design where it is a part of the gun frame.
The integrated feed ramp is the preferred set up. The other major cause of problems is the magazine. The lips and follower on 45 mags are critical. The round has to stay in the mag long enough for the fired round to be ejected, then, as the slide moves forward, the round has to clear the magazine lips after the slide is past the ejector, have the bullet nose ride up the feed ramp as the cartridge rim slides up under the extractor. Fixing flaws in this ballet can drive an inexperienced gunsmith to drink. Even experienced ones have been known to pitch the troublesome magazine rather than waste time trying to adjust or fix them.
Today's 45's have far fewer of these issues as machining techniques have made tremendous advancements and negated a lot of the hand fitting of old. So once again, someone has asked what time it is, and I have explained how to build a clock.
OP, either choice should produce satisfactory results, keeping two things in mind: most 45's do not come with a target quality trigger until you get in to the high end guns, and not even a $4000 custom special can overcome bad ammo.
