Depends on what you're comparing them to. I've bought four (so far): the Japanese mini-LP-sleeved Drums & Wires, Skylarking and Nonsuch, and the UK jewel-cased Dukes of Stratosphear set (Chips Off the Chocolate Fireball).
Speaking strictly in terms of CDs, I think these four at least are much better -- fuller and richer -- than the earlier standard CD issues. (Skylarking is also available on one of MoFi's better gold CDs; it's more of a toss-up between that and the new remaster.) The best news is that they don't suffer from too much of the over-compressed and -NoNoised sound of many current remasters.
That said, I also have original UK vinyl of Drums, Skylarking, Nonsuch and the Dukes' Psonic Psunspot to compare as well, and ... the new CDs don't measure up to those. But they come closer than the earlier CD issues did. If all you have are the older CDs, I'd say it's definitely worth trying one or two of the new ones to see if you agree with me.
BTW, on XTC's official web site (
http://www.xtcidearecords.co.uk), you can order copies of the remastered CDs autographed by Andy and Colin for cheeeeep ...