I was also a regular passenger in G-CORP (and it's predecessors, and it's successors) - by regular I would suggest an average of 12 flights (6 return trips) per month between 1992 and the present. The previous Jetstream 41 was cramped and noisy (more so than the 18-seat J31 before that for reasons that weren't clear). For the 45-minute flight the ATP was perfectly acceptable in terms of noise and comfort. The BAe146s that succeeded it were even more comfortable - I'd happily own one of these as a personal runabout if I became a billionaire. But after the 2010 SDSR the 146s were replaced with Embraer 145s; aircraft which amply demonstrate why Brazil should be used as a nuclear missile test site. The 145s are really, really horrible. They are noisy, cramped and have oleos seemingly filled with granite. If you don't sit with your spine properly vertical during impact you will suffer spinal damage. They are also ridiculously tight for take-off weight (apparently because the short run from hampshire to lancashire is at the extremes of its range with reserves). Restrictions on carry-on baggage weight are so severe that many people decide to drive, because there is no point in flying north if you can't also bring your laptop and documents.
In a choice between the two I'd frankly I'd rather have the ATP than the 145.
PDR