I'm not at *all* unhappy with the instrument. It's *really* nice. I'm unhappy with marketing. The rise time is specified as "calculated" in the datasheet and the conventional 0.35/BW rise time is listed. But rather clearly the MSOX3104 rise time specification is measured. Were it calculated, it would be <350 pS.
Using my out of cal 8648C at -20 dBm it appears to be down about 2 dB at 1 GHz. I've got a 438A with 8481D and 8482A heads which have fresh cals with data, so I'll know more once I retrieve the cal data from Keysight and start testing everything I have against everything else I have.
I had planned on selling my Instek MSO2204EA, but I may reconsider as it will do much longer FFTs. That decision will take some study as I have an 8560A with TG. So I need to come up with some torture tests.
I always have found the 0.35/RT bit rather suspect as it makes a lot of assumptions about the rate at which the BW falls off.