I have a large trance and am 6ft, I also have a large Reign which is equivalent to an XL trance. When seated, the distance between my saddle and bars (in drop and length) is the same. The difference comes when you stand up, the Trance is 20mm shorter in the reach which is noticable. What I’m saying is you can do a lot with saddles and stems to shorten/lengthen bikes.
The large trance will be more stable at speed compared to the medium, the only concern would be the seat tube height and being able to get the dropper post low enough. The 2015 giant dropper has a 25mm layback (I think) which will make it difficult to get the seat close enough to the bars, a reveb is inline so gets round this potential issue. You will almost certainly want a stem shorter than 50mm, probably close to 35mm.
Also it was very low at the front compared to anything else I have ridden.
Its useful to have the option of running the bars low without having to run negative rise stems and bars!. 120~mm head tube on a large is a pretty sensible number. I sold my Sherpa as I couldn’t get the bars low enough!