They do have the same 25yr guarantee as copper !!
Yes. But all that guarantee covers is the price of a new fitting. I found this out the hard way when one blew on me a few years back and caused a few hundred quids worth of repairs.
To answer OP....
I make a big deal out of not using them when I bid for a job. Most of my customers are old folk and dont mind paying to have the work done using endfeed and the odd compression. I've had quite a few push fits fail on me over the years so I dont trust them and I wouldnt have them in my own gaff.