Living in London, I have never had the dubious pleasure of travelling on a Pacer. How would travelling on one be best described?
As my local preserved line is the Bluebell, it's very unlikely that one will appear there, despite the appearance of the odd diesel over the past few years.
Similarly for me, living exclusively in the South-East/Anglia/South-Coast areas, I had not experienced travel on a Pacer, - that was until last year.
I managed to make two very different trips in the North-West, - 142018, from Preston to Blackpool South, which was a pleasant branch line experience. Although I'm not one of those who obsesses about seats lining-up with windows, the unobstructed and airy view from most seats was very welcome and quite appropriate for a low speed journey with regular stops.
The other trip was on a less well fitted out 142, (didn't get the number but it was coupled to 150114) from Victoria to Hebden Bridge. The seats were individually upholstered but with lower backs. It rattled along at up to 75 'ish up to Rochdale and Todmorden. It seemed quite capable of maintaining linespeeds and climbed up Miles Platting Bank effortlessly. There were bouncy moments and the combination of that with the open nature of the view made the speed seem a bit of a dash at times.
Whatever the DfT says about removing Pacers from bids, I suspect that they will remain in place on lines that don't have really good BCRs until they are life expired, so limited investment funds can go where there is a better case.
A far more likely long-term use would be on preserved lines, particularly where there is a semblance of a public service rather than just enthusiast days. They have relatively low running costs and at light-railway speeds, track wear and suspension issues coulsd be manageable. For passengers, their high passenger capacity for their size and weight and the clear views would also make for pleasant journeys, even previous regular passengers who were glad to see their eventual disappearance from commuter services.
