Oy ve.
First off... There are not going to be any military style rifles with .223 chambers. Even old Colts that are marked .223 actually have 5.56mm NATO chambers. And no, they are not the same.
FN makes the M16A3/4 rifles in service and some M4 carbines, Colt makes most of the carbines. Other rifles are currently in service, some like the HK416 are in 5.56, some are in 7.62 such as the ScarH that Marsoc just adopted.
A Mini14 is a sporting rifle. I've had three or four, still have one. They are not made to military specs and are not as survivable as ARs made to milspec. Parts are not tested to the same level of QC. They are not meant for combat.
If you're saving your pennies for something, the SCAR series looks promising. Personally, I'd wait for the H models to become commercially available.
Despite some problems with the M4 carbines, they've been quite popular. Army marksmanship training is actually pretty good these days and first class optics are fielded. There may have been some problems with GI Green tip out of short barrels, but new ammo has come along to solve this problem.
Colt has some new gas piston guns and such coming out, including a gun with a quick change barrel meant to be essentially a light weight replacement for an M249. There is also a series of 18" barrel AR subvariants to bridge the carbine/rifle gap. In terms of things available, these are rather neat.
In terms of what you can go out and buy right now? Shrug. Colt 6920 and get some good optics for it. As close as you are going to get to an issue M4.
The Izzies dumped their Galils. Century brought the parts, hence the sporters. What did they get instead? M4 carbines.