One thing to note about the STI Spartan [or the Armscor RIA Tactical] 1911s that I didn't see mentioned: the sights. The sight cut for the STI Spartan/RIA slide is Novak-like. It is the same angle and width, but is cut about 10mm deeper into the slide. For example a 185 front Novak sight, when fitted to an RIA or STI Spartan [ria] slide is now a 175 front sight height.
This makes it a bit more cumbersome to change sights out.
I have an RIA Tactical that has a smooth and crisp 4lb5oz trigger, with night sights. I am VERY happy with it. I have the STI Spartan slide on a 1961 DGFM Sistema Modelo 1927 and like it. Both have the same sight cut, from the same maker.
One concern I have about the earlier advice to add a 9mm top end to the existing .22 RIA 1911: feed ramp. From building my Caspian 1911 and other readings, the 9mm 1911s have a different feed ramp angle/profile compared to the .45acp. I don't know what the .22lr RIA 1911 frame has for a feedramp cut. If it is set up for the .22lr and for a .45acp, then a 9mm top end will probably have feeding problems.
CZ makes a nice pistol. I find the DA trigger pull too long for my stubby fingers. SA is fine. I have a CZ-knock-off [baby eagle] that has a slightly shorter DA trigger pull and am very happy, but it is also heavy.
Wherever you live you need to know the mag laws. In california, we are limited to 10 rounds [with exceptions]. This means the CZ loses a major point of its appeal over a 1911 in 9mm: capacity. The CZ would have 1 more round than the STI 1911 [IF we could get one: it isn't 'on the list' so we can't, but 1911s in 9mm are 9 rounds usually]. In a 'free state' there is an advantage to the CZ, with 16 rounds vs the 9mm 1911s 9 rounds.
By the way, my favorite 9mm is actually the Browning Hi Power, which you won't find in your price range unless used, and they have LONG resets on the SA trigger. They are an acquired taste, which I've acquired.
I'm interested in a 9mm 1911, but see no great rush for myself to get one. I too value variety. Despire half of my semi-auto collection being either 1911 or BHP platforms.
Good luck, whatever you choose.
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