I had an original model year Trance. Like many others I swapped the fork out, in my case for an AM1 with Travel adjust. I found 130mm too long actually for most XC / trail stuff; but then again Marz are slightly longer axle to crown for a given travel than others anyway. Wound down to about 115-120mm it was fine. Then the fork went kaput and I swapped back to the stock 100mm Reba but moved the internal spacers to get it to 115mm and loved it.
I only swapped it out earlier this year for a Fuel Ex partly because I wanted a change and partly because the Trance I had was a bit heavy, particularly before they started hydroforming tubes and machining out the shock mounts, etc. The only reason i didn’t get another was becuase I don’t like the aesthetic of that pot-bellied down tube. I’m still sometimes a bit unsure I made the right choice….
As to the geometry / fork length question; I quizzed the Giant guys at MM a couple of years back why they continue to spec 100mm forks on these when everyone I knew swapped them out for longer, and their answer was that that was how it was designed, as a steep angled XC bike. The Trance X, which was just coming out was supposed to fill the niche that people were using their Trances for. Still doesn’t quite fit right imho, I’d had said the Anthem was their XC bike but it’s their choice and their marketing after all.
I’d wholeheartedly recommend at least a test ride on one.