jazzbass12, so far I have only done a really basic and crappy live line-input recording using my old, around-the-back-to-get-to-the-elbow recording method.

I use 2 mics to record: an MXL 909 for vocals and a cheap kick drum mic for acoustic guitar. What I used to do was, I would run the MXL 909 into a cheap Peavey mixer for phantom power and then ran that and the kick drum mic into a 4-track. The 4-track doesn't have phantom power, so that's why I used the mixer. I'd then run the audio out for each track via line-input into the computer one at a time. The headphone jack on the Surface Pro 2 is a dual jack, so it supports both input and output. If you have a headset that can take advantage of it, it works really well. However, I am looking to drop all of that nonsense and go with an actual audio interface to make things simpler and more efficient.

I have an MTRACK Quad coming in sometime soon, and that's when I plan on starting the video review. I'm hoping to bypass all the prior nonsense I used with recording to a 4track and then running tracks individually into the line-input, and then mixing it down... I want to be able to just put both mics into the MTRACK Quad and line both of them at once and be done with that whole process.

I am currently using ASIO4ALL drivers, but I will install the Quad's ASIO drivers when it comes. ASIO4ALL should work fine, but I always install the manufacturer's drivers just in case. The Quad also supports MIDI, so I can run the Akai mini through the Quad as well.

I'm still having issues with the MPK mini in Sonar's default hardware controller surfaces setup, but, earlier today, I was able to learn how to map the rotaries easily using the AZSlow controller surface plugin. So, at least that's one bird down.
 
-edit-

I also have an actual desktop PC that I can and will use for serious mixing. My plan with the Surface Pro is to be able to use it to do quick recordings on the go and also to be able to easily record vocals. The Surface Pro makes no real perceptible noise since it mostly uses passive cooling and even when the fans are on, they're impossible for me to hear, so I would think the Surface could be great for capturing vocal performances without creating any additional noise. My desktop's fans are simply way too loud to ever be anywhere near the mic when I'm recording. I don't notice them when I'm playing games, but I certainly do when trying to record singing.

Easy to add an external monitor, blue-toot mouse, and usb interface.

I know a bit OT but:
 
I can say this... that the surface RT model works great as a REMOTE DESKTOP for X3 running on a desktop... I carry it around the recording room all the time and start and stop recording sessions without being at the desk.  Quite convenient, especially when I am recording myself playing guitars or keyboards.
 
Jim
 

I haven't used it but I have purchased a 23" touch screen monitor for use with X3 (Windows 8.1).  It's not prime time yet.  The 23" monitor doesn't have the real-estate so I can't imagine a smaller screen would work out any better.  Of course I could be wrong about the surface pro!  I'm hoping the coders are looking more deeply into touch screens. 

I'm now considering a Surface Pro 3 and I'm wondering if any other Sonar users have any updates or input about their experience with this combination.  I'm also curious about the use of MicroSD cards on the Surface Pro 3 to save projects for portability to my desktop.  I would expect that Class 10 cards would be a requirement, but I'm eager to see what others post based on experience. 

Noel Borthwick [Cakewalk]
We have - it works great with SONAR. Depending on which config you get its quite a powerful quad core machine. I think our marketing guys will be showing it at CES if you are in the area.

well... there is no surface with a quad core processor - all the mobile cpus used are dual cores !!!