The general consensus seems to be that the 143s and 144s are better than the 142s but I personally disagree, providing the 142 in question isn't a Merseytravel one. I went on 2 Pacers earlier today: a 3-car 144 from Denby Dale to Huddersfield and a Northern Spirit refurbished 142 from Huddersfield to Batley. The 142 was a far more pleasant ride as the bulky seats on the 144s are too close together, and my knees are crammed against the seat in front even though I'm only average height at 5'8".
There's very little jointed track left around West Yorkshire so the ride quality is less of an issue than in the past round these parts, although the rigid wheelbase can be rather noisy with squealing on tight curves such as the Wakefield link line and the curves at Bradley and Greetland. I'd argue that the ride quality of Mk4s is worse than a Pacer on straightish CWR, though that's generally at a much higher speed than you'd get a Pacer at. I only have limited experience of 143s but a journey from Taunton to Newport was a step too far on one of those! A few weeks ago I ended up going all the way from Huddersfield to Kirkham and Wesham on 2 different pairs of Merseytravel 142s and again that was a bit too much! I was definitely relieved when my Blackpool South train came in formed of a pair of 150s!
One thing I will praise the Pacers for is the great views than can be enjoyed from them due to the light, airy cabins- in particular the seats at the inner end of the non-toilet car which with the bus doors offer a great view of the Holme Valley as you head over Lockwood viaduct. Thats something that will be missed when 150s become the standard on the Penistone line, as they and the 153/155 are the very worst stock to have on scenic routes. They are getting old now though, and as much as I've grown to love them over the years I won't be sad to see them go. I do hope some get preserved though because love them or loathe them, they are a significant part of our railway history.