I have an earlier Bachmann 37 fitted with sound and an Accurascale 37, also sound fitted. The Accurascale is a more detailed loco but I find the Bachmann acceptable, I'm not a rivet counter, and it cost me less than half of the price of the Accurascale, though that was some years ago. As far as weight goes, the Bachmann comes in at 556 grams, whilst the Accurascale is a more hefty 694 grams, some 25% heavier. Unfortunately, I don't own any Hornby Railroad locos, though I do have some from the standard range. The nearest I have to the 37 is a pair of 31s, which weigh 437 and 467 grams, though of course, they are slightly smaller locos.
@Deem, is there not space in your 37's body to add liquid weight or even some solid weights?