No. They are the worst sounding DMU in the UK (Cummins versions anyway), more of a whine than the roar more common with DMUs, particularly inside, and especially when idling (I suppose some of my hatred comes from the various times I sat listening to that sound when on a failed or otherwise delayed 158). From personal experiance they are unreliable (I think I've clocked up more delay minutes due to 158s over the years than all other types put together, and they arn't even my highest milage trains (they are at least 3rd behind HSTs and Turbostars, 156s probably come close). Even when they havn't failed, more often than not 158 related journies seem to turn into a disaster one way or the other. Whilst it's always been Central units I've had problems with, I've done more milage on their Turbostars and about the same on 156s with much less problems (infact I can't remember one real problem with a CT 156). Most of the ones I have been on have been rarther uncomfortable and in bad condition aswell (although that's a lot down to TOCs, again Central, but also Trans Pennine and Northern/ATN). Air Conditioning often fails in the summer aswell. The "tilt profile" makes them seem a little cramped.
They arn't all bad though, they do give a damned good ride (same bogies as 442s and Mk3 DVTs) especially compared to other Sprinters and Turbostars, when the air-con fails at least they have opening windows, and they do look good. Perkins engined ones arn't that bad sounding either. I do like the tip up seat in the front vestibule aswell, spent many a happy hour their on busy CT services.