As Area Coordinator and Match Director for two clubs, I have seen a lot of guns and equipment.
And, while I love to shoot my CZ Shadow SP-01 in ESP, I also like to shoot other Divisions. I do not represent nor do I get any benefit from the following recommendations. This is meant simply to help new shooters.
The Guns I compete with in IDPA and USPSA:
IDPA ESP and USPSA Production: 9mm CZ75 Shadow SP-01 (Matt Mink Version) with fiber optic front sight (Experimenting with Springfield 9mm 1911),
IDPA SSP: Glock 34 with Dawson Sights and on occasion Springfield XDmod2 Tactical 9mm with fiber front sight,
IDPA CCP: 9mm CZ75 Compact SDP L (Alloy Frame) with Tritiums (and for flashlight matches),
IDPA CDP: REmington R1 with CMC 8 round mags, and Dawson Fiber Optic Front Sight,
IDPA BUG-S: 9mm CZ RAMI with Cajun mods OR Sig Sauer P238 with Truglow front sight,
IDPA BUG-R: S&W 442
Carry Guns: 9mm CZ 75 Compact SDP L, OR Sig P238, and S&W 442,
Comp-Tac Holsters, One Blade-Tech Holster,
ALL of these guns are incredibly reliable, and dependable.

My Recommendations are based on what I have seen new shooters operate reliably and easily with few issues:
1) Keep It Simple: Don't modify stuff other than maybe improving the trigger with a drop in kit and adding fiber optic front sights,
2) Use factory ammunition. Reloaded rounds add another factor into reliability and consistency.
3) Pick a gun that fits your hands best and you can easily operate the controls;

My gun recommendations for new shooters that are all reasonably priced. This does not mean any other handguns are bad or unreliable. I have just found these to be less trouble for new shooters and easy to get holsters, etc. Fiber Optic Front Sights for all:
IDPA ESP: 9mm CZ75B with manual safety (DA/SA) with Short Reset upgrades, comp hammer, etc, OR Springfield Range Officer in 9mm, Tripp Mags;
IDPA SSP: Glock 34 with Zev IDPA legal drop-in kit, Springfield XDmod2 Tactical, Springfield XDm 5.25, S&W M&P 9 Pro, Walther PPQ M2 5"
IDPA CCP: Glock 19 with Zev IDPA legal drop-in kit, Springfield XDs 4.0" with ext mag, S&W M&P 4.25" (Now 2.0), Walther PPQ M2 Standard
IDPA CDP: Remington R1 or Springfield Range Officer 45 with CMC 8 Round Mags;
IDPA REV: Ruger GP100 4", S&W 686 4"
IDPA BUG-S: Glock 26, S&W Shield 9mm, Springfield XDs 3.3" 9mm with short mags.
IDPA BUG-R: S&W 442, Ruger SP101 Snubby

Comp-Tac or Blade-Tech holster and mag carriers, 5 Stitch Instructor Nylon Belt.

Hope this helps newcomers to IDPA.
Cody