I bought an Owon NDM3051 (Chinese local version of XDM3o51) a few years ago.
(~200 USD equivalent at that time).
I asked the seller to change its firmware for "global" version.
So, it has same firmware as XDM3051. And the seller said that the only difference was UI language.
If you're not Chinese but visiting China, you can buy such local versions and Owon salesmen support such firmware upgrade for free.
Two thins I disliked:
I could get rid of its noise after disconnecting the fan connector.
Even after fan disconnected, I could feel (almost) no heat on the instrument.
But there was no way to improve the very slow booting.
I also bought Owon's NDS1104 at that time.
It was silent. It was having same firmware as XDS1104, (because it's having language selection menu?)
But it also had very slow booting issue.
For about ~1 year using it, I could not watch its boot time anymore, and decided to move to other brands.
Finally I packed them all and put somewhere in my storeroom.
Now I own Iwatsu VOAC7520 that I bought at ~150 USD last year in the second-hand market.
I'm quite happy with VOAC7520, not only because it's silent and fast-booting.