Yeah, some of the full builds are amazing value- I built my 224 to my taste and it end up costing the same as a brand new bike built to pretty equivalent levels (just not with kit I wanted). And those bikes are now good used buys too. You need to be cautious with DH bikes just because some get the **** kicked out of them then sold on rather than serviced so you can be buying someone else’s bill. Then again, some are garage queens that got ridden twice then parked.
Also agree with Jimjam, you need to be careful with older bikes, I had IIRC a 2007 Ellsworth Dare and it had geometry like you’d find on a 120mm trailbike these days, what a bag of shit it was, I rode it twice then sold it to some other poor sap. Then again my 224 Evo was a 2007 as well and it still felt pretty modern in geo terms- 64 degree head angle, decent wheelbase etc. Suspension off a horse cart but that’s by the by.
Actual hints? Boxxer R2C2/Team are a worthwhile upgrade if you can stretch to it imo, much better than the RCs and not generally that much more expensive. If you get a frame with 73mm BB and 135 rear axle (like my Herb and my 224 Evo) then you can use trailbike parts and that can widen choice, allow reusing of stuff you have, and save money- my Saint 73mms are uncool so they cost way less than 83mm. And I reused my old trailbike wheels as I wanted a light build. OTOH, if you want bombproof and cheap then the DH standards probably serve you better. But don’t obsess over DH specific kit, tons of all mountain/ #enduro stuff is up to the job these days.
Scott Voltage seems to be a consistently good value, proper frame, and very adaptable. Just make sure and get the right rockers.
Zee is really competitive with Saint now. But the Saint mech’s worth the upspec IMO as it’s just so much stronger. I’d sooner get old 9-speed Saint than Zee, you will definitely mash it off a rock.
Oh, er, PS, want to buy some bits? Got a nice set of Boxxers, a Last Herb DH frame, and assorted build gubbins. 😉 The Herb’s probably out of your price but maybe not.