I definitely recommend it. Prior to the Labradar I cringed every time I had to take out and set up my chrony. Not to mention the consistency and issues with lighting. Luckily I never shot it.
With the LabRadar I gather velocity data every time I shoot at the range. Gives me a tone of data I would not have the patience to gather with the old chrony. Or even with the Magnetospeed as I would not be able to measure velocity while shooting groups due to POI shift.
I run a 10,000mh smart phone power pack and get three range trips out of it easily. Use some Velcro tape and stick it on the back of the LR.
As for reliability it has missed two shots out of about 400 rounds fired past it. In both cases my barrel was to far forward. I keep an eye on that now and it has not failed to trigger since.
As someone else has said I find the app marginally useful. Any real analysis I do is done in excel when I download the files from the SD card.