With my apologies to Daniel and Keysight , I personally wouldn't recommend any of their scopes less than 3000 series.
3000 series is amazingly fast, both in user responsiveness and in retrigger time and is pleasure to use.
It also has very short memory, and as such is not good for lots of decoding, or looking at long captures.
But as interactive scope is the best.
I agree that interactivity and snappiness are the strongest point of the KS scopes, and that low memory are there weakest point (do not argue with that).
On the other hand, what is pretty much a single flaw with 3000T (short sample memory) is many times worse with 1000X and 2000 series,
I think you exaggerate way too much.
Fact: The new KS budget 1200-series has exactly half the memory of your, many times more expensive, 3000-series scope.
and also waveform capture rate is much slower on 1000x/2000 (which was one of good things with 3000). So you get worst of the both worlds.
If you are looking at 1000X series class, from A manufacturer you have RTB2000 that will give you 20x the scope in every regard,but for more money, or you can look at the GW Instek MSO/MDO/GDS-2000E that are fantastic scopes, and also Siglent 1000X-E or even Rigol MSO5000 series (still really new, but will be stable in coming months) for much less money and much better capabilities.
I agree that waveform update rate is a really important factor to miss less information. The KS 3000-series is absolutely fantastic with it's 1 million updates/sec, but it is way to expensive for me.
How do the other scopes which you recommend perform?
The RS&S 2000-series (which I really like and consider buying myself); up to 50 000 waveforms/s.
Siglent 1000X-E; Waveform capture rate up to 100,000 wfm/s (normal mode)
GDS-2000E Series; Waveform Update Rate of 120,000 wfm/s
KS DSO-1200-series; 200,000 waveforms/sec
The only one beating them all is the new Rigol 5000-series (with up to 500 000 wfm/s, with some debates)