Joined: Aug 2010
Posts: 12,760
Likes: 2,117
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
Parts availability in Europe is quite different than in USA. So, I can't comment on the XT group compared to other groups because I do not know what else is available. But, I can say that some parts you want to have good quality, others you can scrimp on.
That would mean a bit more work by finding specific components that you want instead of picking one grupo. For example a rear XT hub version M756A is a bargain when available, I ordered one about a week ago. But since that is considered older technology, that is unlikely part of a group package. For rim brakes I usually buy Tektro, you don't need XT level. Working at a bike shop, you can probably find some used parts for a very good bargain price too.