EricStarted with the Pro Chrono. lighting issues as mentioned before, not to mention set up.. The light issue can be solved by adding LED light bars available. results are not nearly as accurate/consistent as either V3 or Lab Radar.
Ran the V3 and Lab radar concurrently for an 8 month period. Overall difference was a 4fps spread (Lab read faster), and reliability (lab reported 80%, vs 99.6% on V3).
I developed an "off barrel" mount, that took care of the velocity vs. group issue.
Was going to sell the Lab, but found a microphone attachment, and now get 95+% readings.
Still prefer V3, due to my setup and ease of use (total setup is about a minute).
Hope this helps.
I have a brand new Oehler chrono that I bought a few years ago and never used it.
If you are interested in it send me a E-mail and we can discuss it. Long before all the chronos listed on this site came out Oehler was and still is a great unit. Its still in the box it came in. I don't know what kind of money you are looking to spend but I believe I can help you out. Contac info later if want it.