I have 2 rifles in .223/5.56: a Weatherby Vanguard Varmint Special with 1-12 twist, and a Mossberg MVP in 5.56 with 1-9 twist. The Mossberg is accurate, but the Weatherby is head-and-shoulders above the Mossberg.
In terms of the Vanguard, I use reloads with form-fired Lapua brass, 28.5 grains of Varget, and a 55 grain Sierra ballistic-tip-type projectile. This load flies flat, and hits hard even at 300 yards. When you start looking for .223s, the world is your oyster...rifles in this cartridge made by at least a dozen companies, and good quality.
I'd suggest you determine purpose, distance at which you plan to use it, and base the selection on which twist would best suit your purposes. Then, look to which the offerings.
Geno