Own a .22 Vet Long and shot a .22 Prophet for about 2 months as part of a review....
Biggest difference is the power output. The Prophet doesn't even have to try to send the .22/25.4gr MRDs over 1000fps, while the Vet Long (in OEM form) has to try really hard to break 910fps with the same pellet.
And you mention the Vet Standard, so it'll be even more limited in power d/t shorter barrel (21inch on the long versus 18 inch on the Standard, if memory serves). So, if you're thinking heavy pellets or even slugs for your 100 yard shooting, the Prophet is really the better option to get the most out of a high BC pellet or slug.
If you're okay with the top end of power output being 38-42fpe, than the Veteran is a more refined experience. (smoother cocking, better trigger, better magazine system).
If you're after POWER, which is where most go when they're wanting to target shoot 100 yards, than the Prophet is the better option.
Prophet's trigger is surprisingly good. Prophet's cocking gets a bit stiff on the higher power output tunes. Prophet has an adjustable regulator (Veteran does not). Prophet is more utilitarian.
Most don't want to admit it, but the Veteran, (again, in OEM format) is really a pellet shooter. Taipan barrels are choked for pellets. I've got 3 sitting on my bench (Short, Standard, Long) that won't shoot the .22/MRDs worth a dang. I've also been part of a project or two on a friend's Vet and it was the same story there, with two different Vet barrels. Taipan barrels are all exceptional with JSBs, 18.13grains and down in weight though. And 18.13s for target shooting off a bench at 100 yards is an exercise in frustration, compared to the MRDs or even lightweight slugs in .22.
Edit: I remember seeing some comments that the slower twist in the Prophet .22 barrels don't agree with slugs....