Glad you are enjoying the new layout, the steamers look heavy and solid works of art.
I find that most of my running is diesel as these are the smoothest runners in the garage. I have a Bachmann 24 from years ago which runs faultlessly even on dirty track. A Bachmann 20 (early dcc fitted) never disappoints, despite falling off the layout . The Hornby steam is an apple green N1 which is very temperamental and geared for 150 mph (mostly useless). The only reliable steam is a Bachmann analogue N class in Southern dull green which ploughs on and rarely hesitates. I have a Bachmann V1/3 but it is rather light and not as good.
The only Hornby I've had that has worked as well as the superb (and cheap) Trix locos in my odd collection is a blue 08 shunter.
Heljan locos seem to start well but run progressively poorly with time (is this the pick-ups and wheels?). I've a Mainline N1 that runs better than its Hornby upgraded version.
When I was 13 I was frustrated at having to push Hornby locos at every session. My uncle was exasperated and gave me some money to buy a Fleischmann diesel - it was perfect and I went German.
I saw Bachmann's stuff and that got me back into modelling ten years ago. I wouldn't buy anything by Hornby except rolling stock after my experiences with their steam and diesels (except the 08)
I've tried US recently on a budget of £30 per loco. Two Bachmann GP's with hoods glide around the track at scale speeds, totally reliably. I was very impressed.
Dapol was a series of returns to find something that worked.
In what other hobby do you pay £140 or more for something that is faulty?