Only because the Dave is pretty old at this point and I'm worried Dave 2 is around the corner.
Buying used is good advice, but I don't think Dave 2 is around the corner. We might see some Dave/MScaler combo pack - and as evidenced from the Dave thread, many find a tremendous amount of improvement with an upgraded power supply. I'd check in there too.
Rob Watts has said he's not going to build a new DAC until he can significantly improve on what he's built. Sure, it's possible that there is a further upstream model with all of the above included - but Chord is selling a ton of Dave's - for a niche audiophile product. I bought mine new a few used ago from Sound by Singer in NYC. He was the only dealer in NY that carried the choral line. Chord used to be very strict with their distributors, but it appears they've changed their policy because of their success.
Now, I can go online and buy it from Moon Audio or Audio 46 (both of which I love), but it just shows how more accessible it's become.
I may purchased some of the additional tweaks available on the chord thread (I already have WAVE Cables, an OPTO DX, M-Scaler, Batteries - and a variety of linear power supplies) (though not the big one - yet).
I fully expect to be using my Dave for at least another 10 years. After I max out my headphone rig (famous last words) - it will do double duty when I build a 2 channel setup.
Truthfully, I don't think anybody who buys Dave as a DAC can go wrong. It's really, really good.
And for what it's worth, I have the 33, Dave and M-Scaler and spent a lot of time with the TT2. You can't go wrong with any of the upgrades (Tubes, M Scaler, Dave). My personal opinion would be to upgrade to Dave first as well.
I just got in the queue to replace my Wa33 SE with an Elite Edition. I will share more after I receive it, but from what I've listened to at shows - I think it's going to be a huge upgrade. Since I've also bought some upgrade tubes (the Psvane ACME 2a3 really settled in nicely), I am done for a while. Or, I might buy a DC4.
