android devices progress by leaps and bounds every year, even 6 months.

simplifed, the progression has been:

android: version 4.1 jellybean->4.4 kitkat->5 lollipop->6 marsh mallow
chip: dual core->quad core->octa core
memory: 1gb/4gb->2gb/8gb->2gb/16gb
"powerful" generally = most expensive and newest.

the "most powerful" box at this time is probably an octa core 2gb/16gb lollipop 5.x.

the trouble with this "most powerful" is there are a no. of apps that do not support the chipset or the android version. in fact, most local iptv like astro-on-the-go, hypptv everywhere, iflix, etc. won't work with newer sets. can say they can't catch up so quickly.

so, why u want it to be "most powerful"?!

it all depends on how u will use it. for light users, a simple basic one will serve the purpose.

some will look for large memory to dump in all sorts of apps and never have to clean up.

some look for 3D, 4k and hd audio handling.

some look for proprietory apps, pre-installed apps, even iptv subscriptions.

do read this thread from page 1. don't get the idea that by buying the most expensive box, all will work well. not at all. becos these boxes are software driven, u need to know how or get help to make it work well.

VidOn XBMC.

Haven't used the software, but I remember others on a different forum commenting it works... Anyway;
*Sure the files are properly ripped & encoded? Try ripping yourself.
*The official KODI has an area in its settings to enable the Blu-ray menu vs a simplified menu. Tried that & even while playing, no access to the menu?

IMO, VidOn XBMC is still your best chance so tweak that. Could be a hardware incompatibility as well.

what device r u using?

this one?
http://www.minix.us/products/NEOXU1.html
what about 2d iso?

do u get hd audio, i.e. dtshdma or dd truehd?

the native player should be able to handle these bdmv/iso 30-50gb files.

no need other players like kodi or vlc.
and i think it is normal u dun get the full menu like disc on bd player, but u should get the menu for playlist, audio tracks, subs, audio settings, etc.

are u sure u did not miss some button that brings up some menu?

Well, depends on the encoding.. Most encoders don't include the menu as downloaders are far more concerned with pq, sound & subtitles. Also not all .iso or torrent files are truly full Blu-ray "dumps". For example, the full Blu-ray dump of "The Martian" is 45GB, has 658 files, files which includes the .m2ts, extras and menus. If not uploaded in a certain structure, the menu will fail to display.... Played with the appropriate player, all included features will be available. Tested on PC with PowerDVD Ultra.. Works..

P.S The forum has a thing against links to questionable content...

Oh I see.. Thought you were after the default Blu-ray menu that comes up as in a regular Blu-ray player... Showing scenes, chapters, extras, etc.. On switching between 2D & 3D mode, KODI has support but a limited on Android.
On the Neo X8-H Plus, I remember being able to play a 3D file using KODI & switching as above, can't remember if it was .iso or .mkv.  Reviews by AVForums and CNXSoft confirm that the Neo U1 is indeed capable of 3D iso playback. So might want to check that file or video settings. Especially since the Neo X8-H Plus could do it.

With TotalMedia Theatre 6 on my HTPC, 3D iso files can be toggled to 2D playback. Menu is just like on a real standalone BD player.

ya, me too.

i went to the cinema a couple of times to watch 3D, came out uninterested.

never bothered since, i even avoided 3D capability on my tv hunt.
about the 3d iso files... i doubt u can do toggle with 2d like BD discs.

i have a ton of 2d iso/bdmv's - all play good with simple menu of playlist/audio tracks/subs - good enough.

Ikr.. I also saw a couple of movies at the cinema in 3D & went.. Meh"..    Alas, thought it'd be better in the living room, got a 3D TV, still wasn't impressed. Perhaps, my expectations are too high..? VR tech, now that's more like it.. Tried the Samsung Gear VR set powered by Oculus + an S6. Nice..  .  The Pacific Rim Jaegar Pilot experience for me was truly impressive. Made me feel truly immersed in the Jaeger..
Features like that are where the HTPC shines... It's more of a Windows advantage over Android... Thing is, as advanced as the Android OS is today, especially with all the fragmentation.. It's still not truly ready for the living room. Advances in hardware & software should bridge the gap.