I've met good and bad, the good mainly being the 'proper' reservists i. e from civvy street who make up in enthusiasm what they sometimes lack in knowledge. The 'not so good' being some FTRS who couldn't make or didn't want to make the adjustment to civvy street.
What does need weeding out are the weekend warriors who have absolutely no intention of doing anything remotely connected with Ops of which I suspect the Army has more of a problem. My brother ( Regular Army REME) did a tour with a TA RLC unit in which he reckoned about two thirds were only in it for the money or the fun bits. He'd spend a week prepping for a weekends trade training to have 4 people turn up, if it was a day on the range however 30 would turn up. Likewise I've got two nephews who are both in the TA/Army Reserve, one for 15 yrs, the other for 12. Neither of them has ever done anything ops-wise. Hardly a good return on the investment!
My wife worked with a girl who was RAuxAF for about 6 years, supposedly as a supplier although she never went near a supply sqn. All she seemed to do was 'training' although quite what trainjng it was was never really made clear- she wasn't even able to select the correct fire extinguisher on the company training session. Something a regular recruit would be taught in the first few weeks at Halton. Again, hardly a good return on the money spent.
I guess with the many different types of reservist there's no easy answer- much like the regulars; some good, some bad.