I bought one a few weeks ago. Overall, I'm really happy with it! It's definitely not perfect indoor or outdoor, but its whole deal is "within 2.5% of Trackman's #s for 2.5% of the price," and I think it has reasonably matched my expectations.
Outdoor, the shot tracer is fairly accurate about 85% of the time - there will be some random ones that just don't look right at all. I'd say carry distance (especially with short through mid irons) is only a few yards different, and it's consistently different. For example, on the course, I expect my 8i to carry 168 and the Rapsodo MLM will