They are of course, but the only multiple unit manufacturers that have attained reliability figures comparable to those of the old BR era fleets being retired are Siemens and Hitachi. With the exception of the Nova 3 which isn't really a multiple unit, no CAF, Bombardier or Stadler unit of the current new generation has reached the reliability levels attained by things like 319s, 321s etc. Those units don't exactly have a stellar track record and most of these fleets, including the 755s, have now been in service for a year or more.
Here's how the GA fleet stacks up so far: