To be fair I've been on a FGW 150/2 and they looked in pretty good condition, especially when compared to LMs 150 (pre-refurb)
Internally there still in good nick - and it shows the quality of FGW's refurbishments, but it's the exterior i'm talking about. And not just the rather nice local lines vinyls. Some of those 150s are gaining some rather unattractive rust spots - and if the body starts to rot...
Note, i'm not exactly blaming FGW for this, as Wessex Trains body maintenance regime could really be described in a bottle of filler.
LMs 150s will have been in a better condition externally, not so much down to NX's maintenance regimes, but more so because they've never had full body vinyls stuck onto their bodysides - BR Reggie Rail, BR Reggie Rail / Centro, (((Central Trains ))) Lime liveries, nor regulary run near areas of salt spray being blown off of the sea. And when you've got vinyl which has been stuck onto the rubbed down steel bodies - which then develop leaks & spots where water can result in getting stuck, it dosent bring pretty consequences.