As a regular traveller on the Mk 4 sets, I have yet to be impressed by a single detail of them.
I'll give them one credit though, and it's not much of one. The onboard temperature, while it can be stuffy, is nothing to the claustrophobic, severely uncomfortable extreme heat of the wretched ICRs, which only very rarely are a comfortable temperature. They are frequently - and I have this on good authority - over 22 degrees. Also the toilets are not ventilated. Try using one after someone has done their No. 2s in it.....
I was on an ICR the other night and I know for a fact that it was actually measuring at over 22. That is bad enough, but compared with the adjacent coaches, the one I was in was WAY hotter.
Why can't we have trains these days with opening windows? I'd rather do Belfast to Cork in a 2600, either in Roses or Quality Street livery, than one of these stuffy tin tubes.
Rant over, for now.....