I don't compete. But I do a lot of training and a minimal amount of instruction. Over the last several years, I have experience with PACT2, CE PocketPro2, CE Protimer(Blue update without bluetooth), CE ProTimerBT, CED7000, Shooters Global and the Mrs just gifted me a Kestral KST1000 a week ago.
Rankings in my opinion
Simplicity:
PACT
Features
ProTimerBT
Settings Navigation
Kestral
Neatest Integration:
Shooter Global
Pact: No random delay. Instant start, or Delay is 3 seconds. There is no changing this and it's not discounted enough in comparison to other timers for limited functionality. Only 1 string of fire is recorded/saved
PocketPro/Protimer: Several adjustments available in comparison to PACT. 4 or 6 button interface is a little clunky, but once you get the hang of it adjusting par times and delays aren't an issue
ProtimerBT: Integrated BT to upload to Practiscore, Headphone jack for dryfire, LED for visual stimulation is cool when muting the beep.
Shooters Global: 5 button design makes navigation just as inconvenient as the PACT but is offset by video integration in the app so you can overlay your timer info into videos. Really neat. (Have had one fail within 3 months of use by instructor cadre member)
CED7000: Super small, usb charging, navigation isn't my favorite but its a step up from SG. Integration into RF Panel for competition use is neat.
Kestral: 2 SCREENS!!!! 3 par times, can adjust mic sensitivity for dryfire (and it works!), TONS of strings of fire recorded and easily compared on the big screen. Multiple settings you can select as presets to work different and settings without having to adjust multiple times per class/student. Save them and name them, and I'm sure a lot of other features I haven't tried. My only complaint is it runs on 2x cr123. I am used to 9v. Not a big deal, but one more set of batteries to keep in the range bag and not as easy to grab at the gas station if needed in a pinch as a 9v
If you need a timer, and dont need it to be feature rich, get a PACT. They hold up ok and do their job.
If you need a basic tried and true workhorse that will take a beating go with the Competition Electronics ProTimer
If you do a lot of video for instaface/twittogram Shooters Global makes sense.
If you are willing to pay for feature rich and a ton of convenience the Kestral is the bees knees