I do some very much testing of IPTV with both OE 2.0 OE 2.5 and OE 2.6 boxes and images.
When it comes to IPTV perfomance i can say that there is no bigger diffrence between most images and most Boxes.
I would rather claim that the Dreambox One and Two do perfome very good.
In my tests the provider is the main issue and the common misstake that ServiceApp is the IPTV
It's still servicetype 4097 that is the most stable for IPTV. And for DreamOS you also can try the python code helper servicetype 8193.
Stick with .ts as streamtype
When it comes to plugins there is no diffrence.
The most used plugins like
Xstreamity by KiddaC
XC Plugin by Lululla
Are alle adapted to DreamOS and performe just as good on all systems.
In all my test i would say the Blackhole is the best image. based on the fact it's sorting out bad providers quick since it's the most picky image.
But for the common user they would probably say the opposite. My recommendation is to use test lines
Try and if the provider have issues then just move to the next one until you find a good provider.
And choose the box and image you like best for your regular use and not based on IPTV perfomance because what's not working
in one box/image will most probably not work any better in the next one :)
But some boxes can also boot into android and there you can see some real deiffence between what Box you are choosing.
If you are using IPTV only i would recommend a pure Android box and here DreamTV Mini UHD is a very good choice