IMO The Aristo 0-4-0’s are always a crapshoot. I’ve had around 10-12 of them over the years. (And still have 2.) Everybody who claims they have one that runs good are probably right, and those who claim theirs were turds probably are as well. I’ve had a few that ran perfectly, some that waddled, some that lurched, and some that were pretty much DOA. The quality of fit and finish was all over the board as well.
Best I can compare it to was '70’s and '80’s Fords and Chevys where if you managed to avoid one built early on a Monday, late on a Friday, or on a day either side of a holiday, then it was a pretty good car… if not, you better have liked the coffee in the service lounge.