Rob I was going to get the Motu XT as well but ended up picking up a Steinberg Midex 8 which also works great. Steinberg have written Win 7 drivers for it even after it went out of production. That works well on Win7. They have some slick front panel features not found on others. I am wondering if once I go to Win 10 the Midex will still work. Do most Win 7 drivers run on Win 10?
Timing is everything and it is important to get that midi interface running well in terms of midi latency and also how accurate the start of midi notes are in relation to audio and the metronome.
It is when you play live and how well those performances are captured and played back that is also important for me.
(with and without the click) I am a drummer turned added keyboard synth player so I have a strong sense of this timing and it how it feels. I use Studio One and I think it is great in this area. There was a thread over on the Presonus forum about someone getting midi and audio timing out by 30 mS from each other. The audio always being late in regard to the start of the midi note. That prompted me to test and adjust my system.
Another good thing to do is get a PCI based USB card and run the midi interface on that instead. It has no interference with any other USB devices then. Running nicely on its own. I found anyway. My audio is on a PCI card too so there is nothing on my USB buses anyway. The various pairs of USB outputs on the back of a desktop computer are often on separate USB buses too. Try to get the interface running on its own USB buss.
I am getting sub second mS timing down to 0.2 mS and in many cases 0.1 mS. Sometimes it varies by a mS or so and this may be due to midi jitter but on my system the midi note start is always early to the audio by the same time (approx 0.2 mS) and does not seem to jitter around.
These figures are also for one synth playing one part too. Once you start sending multiple midi channels down a single port these note start times can and will get altered and delayed more. Use up your 8 ports with one synth only one each port and one midi channel of data only. I have got 6 hardware synths and 2 computers as virtual instruments on all 8 ports. That is a lot. Hearing 8 parts playing back before you even turn on any virtual instruments is a very big sound. And it is all happening on the midi side of your program barely taking any resources away from your audio system in your DAW. Working this way with synths allows you to compose create and edit the music so easily. Tempos can be adjusted in a flash.
It is good to do some tests and see how the midi side of your setup is running and how accurate it is. It is also good to test the latency of your synths one by one. eg Compare the start of the midi note to when the audio first appears. It is nice to be able to adjust midi tracks timing wise in your DAW and get them to play early by the synth latency times putting the audio more where it should be. Studio One lets you offset the midi timing and audio timing in your system. Sonar would have it for sure. So if your midi note start times are say 3 mS early compared to the audio, you should be able to adjust that by adding 3 mS to midi timing and then it ends up within tiny fraction of a mS compared to audio. That is what Motu mean I think for the spec of sub mS timing accuracy as they report in their advertising. The Midex can do it and so can Emagic Unitor 8 too. I think Unitor 8 drivers stopped working a few Microsoft OS versions ago now though.
I have a Unitor 8 running on another Win XP 32 bit machine on the serial port and it is fast too. Under Logic it works great. Midex
(LTB - Linear Time Base) and Unitor
(AMT - Active Midi Transmission) have the ability with Cubase and Logic to be able to improve midi timing by a factor again. Those programs send the midi notes early to their interfaces and then the midi note start times are adjusted and let out to be all be super tight on all 8 ports. As far as I know Express XT does not have that ability but the timing over 8 ports should be excellent anyway. My Midex does not operate that way with Studio One either so it is operating the same way Express XT would. And it is excellent.
The Express XT is an obvious choice for me too if I have to go to Win 10. I have heard they are very reliable and having an internal power supply is a nice plus too.