I rarely use 700s, however when I have I’ve invariably found the interior too warm, especially on anything warmer than a cold day outside. In particular there’s been occasions when the air conditioning didn’t seem to be doing much at all. This seems to be in contrast to other Siemens units where generally it’s pretty effective and seemingly reliable.
For starters the air conditioning could quite happily be set slightly colder.
By comparison a 365 is bliss as the opening windows avoid all this. Personally I prefer the extra noise as it drowns out irritating passenger noises - on a 700 one can hear other conversations from quite a distance away, no doubt anyone using the declassified first (aka the GTR staff mobile messroom) will have heard all about how awful GTR is!