I gave it a go for you today. They continuously add features so it would've changed a lot since you used it.
Impressions, it works best if you mount it high enough that it can see the opposite service line directly (ie not viewing through the net). This is pretty high on the fence so not easy, especially as you can't really see the screen. Works just ok with the front selfie camera. If you have apple watch and iphone you can use watch as a viewfinder and start and stop controller. Also adds the session to your fitness app as a workout.
You need to pay for hd or highframerate videos and some of the analysis, I think it can give you stats and cut out the junk time automatically in between points.
On the 6 or so serves I tested it on it was pretty accurate on serve type and placement in court, although it drastically undervalued the speed of my (warmup) serve, only 75mph my hat, they must have been 130+
IMO if you are into recording your matches, match stats you'd be mad not to use it, it is a fantastic app and well worth the price. As accurate as you could expect it to be and generally very accurate on type of shot hit. Big thumbs up from me