I've always favoured solvent weld waste for plumbing the waste from sinks, showers, bathes etc, especially in areas you can't later get to (under the floor, behind panels etc). Obviously, you need to have some fittings with the rubber/plastic rings at points you need to disconnect to, for example, clear a U bend or bottle trap, but for all other fittings, solvent weld, if done correctly, seems to be fit and forget.
I happened to look at some push fit fittings today - not for use in the house (to build a converter for a motorhome waste outlet) and saw a fitting which, while ideal for my job, I'm not sure I'd trust long term tucked away in a area I could get at. It sealed via internal O rings, which simply sealed (hopefully) against the outside of the waste pipe as you pushed them in the fitting. In my application, the odd drip wouldn't be the end of the world, the converter is outside the vehicle. However, if you used one of these in your house and the O ring was damaged- perhaps due to a burr on the cut pipe, or perished in time, you could end up with a long term leak you wouldn't know about until some damage had been done.
Unlike the fittings with a screw collar, in which the seals can be seen before you do final assembly, the seals are hidden in these fittings.
Obviously people use these beasts, they were on sale in one of the 'sheds', which had a good range of them (the reason I went there- I was looking for ideas to solve the problem). But I'm curious, has anyone seem one of these fittings fail?
I suppose the same is true of push fit fittings for clean water- again something I've not used, favouring solder fittings in hidden places and compression where disconnection may be required later.