64channel per MADI bus is already nice, for single speed recordings you can connect i.e. 8 Octamic XTC or other MADI devices, for double speed still 32 channels available = 8 XTC.
If this is not enough, then there are products supporting up to three MADI busses like the HDSPe MADI FX which has even an FX chip on board. And even RME products like the MADI router exist which give even more flexibility and - if I remember right - also offer redundancy features.

To be fair, the connection between
- AVB devices or
- AVB devices and AVB switch or
- AVB switches (forming up your L2 network)
are also physical connections (Ethernet cable). And this usually even requires AVB capable switches (if we do not talk only about the connection of only two or three AVB devices).

Every technology has their advantages and you need to look what features please you more.

You could see an advantage in MADI, that no special switch infrastructure is needed, lowest latencies and you have a optical fiber based cabling infrastructure which is fully dedicated for audio.

Maybe some other aspects for the dedicated cabling of MADI devices:
- MADI cables can even be 2km long between devices (*)
- if you order the devices with single mode modules then even much more
- wIth optical fiber you even have a galvanic isolation

(*) ok, here in my home recording studio 1-2m OM3 or OM4 fiber cables are enough
But if you need in a building cabling between floors ... and if you do not want to exchange the existing LAN infrastructure to replace all with AVB capable switches ...

In contrast to that Ethernet cables usually support a cable length of 100m (in most cases well enough).

Remote control capabilities you usually need with Mic preamps as there are more parameters to set compared to an AD/DA converter. 

If you use the UFX+ in combination with the Octamic XTC, then you can i.e. remote control the XTC via MADI (by "MIDI over MADI") and the possibility to integrate the XTC as AUXDEVICE into TotalMix FX. By this you can control every important parameter of the XTC and store / recall it by TM FX snapshots as if the XTC is really part of your UFX+.
So MADI doesn't only carry the audio data, but by using some otherwise unused bits of the protocol you can remote manage devices and do not need a special / additional MIDI cabling for this purpose.

There is also an alternative solution possible to remote control MADI devices like XTC: MIDIremote.
But you can use only AUXDEVICE or MIDIremote, not both at the same time.
But you could do a mix, especially if you have two MADI busses, then you can use AUXDEVICE for preamps on one bus and MIDIremote on the other bus for other devices which have no AUXDEVICE support.

There are like always many possibilities :-)

Hi Anrei

In terms of preamps, RME preamps have no "sound" / "Mojo" they are known to be transparent.
Simply very good quality without the aim to modify the signal.

So ... if you want an answer in terms of the preamps in what regards they are similar or even equal to each other,
then the 1st step is, to compare the technical data from the manuals.

I think this will bring you much forward in that regards.

UFX+ has very nice preamps, no worries, it was the new flagship interface introduced at RMEs anniversary ...
And RME told, that compared to the old flagship UFX, the analog section has been completely renewed.
So in short, you get very good quality with the UFX+.

If you want to color the sound, then I would do this by mic selection or by getting external preamps or channel strips.
I would say RME preamps generally deliver very good quality and precision
to finally record exactly, what performer, room acoustic and mic deliver.