I previously owned Innovation, but I sold it because I thought the rules were awful (having to print a page of errata on how to use the cards before I started was not good), plus everyone I played it with said it was too swingy.
I have Glory to Rome Black Box, but I haven't played it yet, as it seems to be generally recommended to find someone else to teach you how to play it, as its one of those 'learn by playing' games.
I have San Juan which I love. I will get to RfTG if I can just get past the evil iconography.
I saw that Uchronia is supposed to be a cut down version of Glory to Rome, on the recent Dice Tower 2012 Top 10 with Zee and Sam.
Questions: 1) Is it worth picking up Uchronia as a helpful entry point to GtR? 2) Is Glory to Rome less swingy than Innovation?
GtR is not that difficult once you get it. I recommend reading Ender's Review of GtR. He uses the old cartoony version but I learned how to play from his review and it's actually what made me a fan of him. As you know, the only differences between cartoony and black box is the presentation, gameplay is otherwise identical (I've played both)
GtR can be swingy, but the Black Box introduces rulesets to prevent it. There is definitely more of a focus on long term strategy in GtR than Innovation. Having said that, Innovation is one of my favorites and I'd play it over GtR any day