This is a good adapter for home use. Having been a roadie, I can pretty confidently say the Midisport Uno’s build quality isn’t roadworthy — the attached MIDI cables are about as thin as the RCA cables that come with most home audio equipment, nowhere near as tough as patch cords for a stage rig. But the average home user, who’s not plugging and unplugging in a hurry and stepping on the equipment and such, should have no worries. I have one, and it works fine.
A note about appearance: My Uno’s body (the oval part, smaller than an average computer mouse) is a deep translucent blue, rather than the opaque color in the current photo here on Amazon. Also, the cables are all one color, black, though the IN and OUT plugs are clearly labeled in molded lettering. There are three green LEDs: one that lights up when the computer recognizes the adapter, one for MIDI in signals, and one for MIDI out — handy for troubleshooting.
I bought the Uno to connect my Roland alphaJuno-2 to my PowerBook and play with GarageBand. I took it out of the packaging (a rare treat: a molded clamshell-type plastic package that isn’t heat-sealed, so it doesn’t have to be cut to shreds to open) and hooked it up, and nothing happened. I initially thought that Mac OS X would recognize it automatically, so it took me a few minutes to realize I needed to install the driver software. Although there are drivers on the included CD-ROM, I downloaded the latest version from the manufacturer’s web site, installed, and the Uno instantly lit up and GarageBand informed me (because I already had the Roland powered up) that a MIDI device was now connected. It’s worked flawlessly since.
Simple to use; no extra cables to attach — I think this is the perfect USB MIDI adapter for GarageBand users or anyone else connecting one MIDI keyboard to a computer at home.

I bought the Midisport Uno a few days ago in hopes that it would replace my 15-pin midi connection I have in the back of my computer (with which I have had no problems, I was just trying to free up the PCI slot it was occupying). Anyway, I have since tested it with two different keyboards, a Yamaha PSR-273 and a Casio CTK-471.

#1) My main concern was that there would be latency issues. This was not the case at all. Rather, I never experienced a single problem with latency.

#2) It worked flawlessly with the Casio keyboard, I couldn’t have been more satisfied with it in that respect.

#3) It worked horribly with my Yamaha PSR-273. Imagine using it underwater, or after bashing it with a hammer. Completely inoperable with this keyboard.

I called M-Audio’s tech support line, and they quickly admitted that the device doesn’t work with Yamaha PSR keyboards. He also mentioned that they don’t work with another Yamaha model line (other than PSR), but he claimed not to be sure as to which one. He suggested I buy a Midisport 1×1 as it has none of the known compatibility issues that the Uno has, but I have yet to test it.

Bottom line: If you’re not using a Yamaha keyboard, you shouldn’t have any problems. If you ARE using a Yamaha keyboard, it’s very likely the Uno isn’t going to work for you (100% likely if it’s a PSR). If you are willing to use a PCI-slot-based piece of hardware, I suggest a cheap soundcard with a joystick (15-pin) port in conjunction with this set of cables: http://www.amazon.com/gp/product/B00008VF52/sr=8-4/qid=1149323626/ref=pd_bbs_4/104-2313201-5844738?%5Fencoding=UTF8

If you’re using a Yamaha keyboard but you still want to connect via USB, you apparently have to get the Midisport 1×1 http://www.amazon.com/gp/product/B00006I5HD/ref=sr_11_1/104-2313201-5844738?%5Fencoding=UTF8&v=glance&n=11091801

Hope this helps.

First off, i plugged this into my macbook pro using a microKorg and it worked seemless on Logic Mainstage……

until i started hearing noises i shouldnt be hearing. oh by the way, it has problems with sustain. this excerpt comes straight from M-audio website:
Note: M-Audio has identified a defect in a manufacturing run of its popular MIDISPORT UNO 1×1 MIDI interfaces. The defect affects only the MIDI input and causes the MIDISPORT Uno to distort incoming MIDI data resulting in random notes, inaccurate note on/off messages, as well as pitch bend.

The following Serial Number range of USB MIDISPORT Uno’s is affected:

From: S/N 31805709001 To: S/N 45805704080

The important Numbers to reference are the first 3 digits. The third digit MUST be an eight. So we’re looking for numbers 318, 328, 338, 348, 358 etc up to 458. What are the FIRST 3 digits of your SN?

Please check for the Serial Number located on the bottom of the shell pack, next to the Bar Code; or if the packaging has been discarded the Serial Number is also located on the bottom of the actual UNO device.

If you have identified a Serial Number within this range of MIDISPORT UNO product please contact your dealer or the original place of purchase to return the device. M-Audio has requested that dealers extend their return policy to any customer who has purchased a defective product within this Serial Number range

Please note that until recently, MIDISPORT Uno’s did not have Serial Numbers. If your MIDISPORT Uno does not have a Serial Number, or if your Serial Number is outside of the range listed above, your unit is not affected by this defect.