No they're not, but they have undergone a longer and more intensive testing regime (both in Germany and here) than most, but still present with large numbers of failures. All this with the benefit of computer-aided design and static testing before running for months on the routes that they are intended to serve. I don't believe the failure regime is the best we could have expected.
I wouldn't regard the frequent reports of
'yet another class 700 failure' by a few posters as representative of the actual defect level on these trains. If somebody here is actually keeping a record of all (or even most) failures, it would add value to any comments about them. We aren't privileged to full details of service failures, but there are frequent corrections to these false attributions from others closer to the operations of Thameslink. There have been 700s taken out of service, with all the disruption that it causes attracting the usual comments here, where the actual facts reveal that it was the failure of another train (319 or Electrostar) or even passenger activities, that caused the 700 withdrawl.
In an ideal world, there wouldn't be any failures of service, but they are a fact of life and unless somebody has
verified causes of such events, no valid judgement can be made of their actual reliability. Some posters here seem to have let their personal dislike of aspects of the class 700s and/or GTR cloud their judgement based only on limited information.
A comparison of reliability is worthless without knowing which class it is being compared with.