Does anyone have experience with this?
I looked into one of those, and the reviews of it were pretty good. I also talked to somebody who used one a couple years ago and he said that it helped him out quite a bit. But in the end, I decided it was a poor choice financially. That device with shipping was around $95. Although it is good at generating random code with which to practice receiving, I don't think it has a provision to practice sending, which is just as important. What I ended up doing was buying a used code oscillator from eBay with which to practice sending, and then using the Ham Morse app for iOS, which has WAY more features than the MFJ code tutor, to practice receiving. You can buy a new oscillator complete with straight key from MFJ, or just search "code oscillator" on eBay to get a big heap of choices. A straight key, an oscillator and a smartphone/web app will give you a lot more features and flexibility than the code tutor, and at a lower overall price. Here are a couple links that might help you:
MFJ code practice oscillator with key: http://www.universal-radio.com/catalog/morse/0555.html (http://www.universal-radio.com/catalog/morse/0555.html)
Ham Morse app for iOS: http://aa9pw.com/ (http://aa9pw.com/)
(NOTE: the aa9pw.com site has a LOT more than just the Ham Morse app, it also has online morse tests and exam tests, all free.)
Morse Code Trainer for Android: https://play.google.com/store/apps/details?id=hunt.morseDit&hl=en (https://play.google.com/store/apps/details?id=hunt.morseDit&hl=en)
Morse Code Teacher for Android: http://www.androidzoom.com/android_applications/communication/morse-code-teacher_exsz.html (http://www.androidzoom.com/android_applications/communication/morse-code-teacher_exsz.html)
I hope this is of some help to you! :)