I'm looking for a scope in the $15-20K price range. I'd like at least 1GHz BW, 4+ channels, 12 bits. Tek has a promotion right now with the MSO44-1.5GHz coming in at $14K and the MSO46-1.5GHz at $16.5K, with options at half of list price. I see the R&S MXO4-BNDL (1.5GHz) @ $20.5K. The LeCroy Wavesurfer 4104HD is $13K with a bunch of options. Keysight has some 10-bit models on their used site in this price range (even up to 2.5GHz or higher), although these don't include probes and I'm not sure about the option pricing. I do a lot of embedded and RF work along with some power supplies and precision analog. I played around with the MXO4 a bit at a trade show and the UI seemed a bit laggy though there wasn't an opportunity to make any real measurements - it does seem to have a ton of features, and there are some in-depth reviews on youtube. I haven't used the Tek or Lecroy yet, but I'm seeing if there's a way to get one as a demo. My trusty MSO6034A has been great going on 15 years, but these days the screen is seeming a little small for some reason.
Anything else to consider in this range?
If you've been doing well with a 300MHz scope for the past 15 years and your only major issue is screen size, I wouldn't rush to spend $10K+ on a replacement.
As others have mentioned, making use of the extra bandwidth a 1GHz scope would provide requires extra equipment. Passive probes, even if indicated up to 500MHz, bring significant capacitive loading.
If the goal is to expand into higher frequencies then the budget should consider active and/or Hi-Z probes as well.
Alternatively, there are some great value scopes in the 12-bit, 200-300MHz range with big screens that would provide nice quality of life improvements. This would keep your budget free for specialized equipment when the need arises in the future.
At the rate oscilloscopes are progressing and prices are falling year over year, I think the optimal strategy right now is to only buy what you need. By the time your needs grow, prices will have dropped even further.