This was a Christmas present, but bought a month before from Amazon. I am a golf beginner and terrible putter and was very eager to try this; I used it indoors on carpet maybe 15-30 mins a day, 3-4 days per week for about 6 weeks this year before the ball return mechanism broke - it will not cock the spring fully, and just makes a lot of noise continuously trying to do so, until you remove the batteries. So who keeps all the boxes and documentation for return 3 months after Christmas? Anyway -
Pros: the auto-return mechanism did what it said, and is strong enough to return the ball for long puts (20ft or longer on smooth carpet?)
Cons: the mechanism for resetting the return spring is quite noisy; wide markings and hole surround give a much bigger visual (and actual?) target than the real thing; the felt mat does not flatten completely so not much usable unless you like putting over wavy bumps (but it works well enough on carpet without it); and most importantLy - it broke down within 2 months of light use.
On balance, the pros would have outweighed all the other cons for me if only it had lasted. The pain of having to find manufacturer's details (no obvious help from Amazon's return process here), find documentation, claim a warranty repair/replacement, return etc. is proving too big a deterrent.