T/C Contender and Encore rifles with aftermarket barrels chambered in 5.7x28 are reported to be tack-drivers that function well. If anyone wants a 5.7x28 rifle suitable for hunting or target use, then this is currently the best way to go, by far.
The Savage model 25 in 5.7x28 was a flop, but this was due to the barrels that Savage used, not the cartridge. By the time that Savage belatedly realized their error, there was enough bad press generated about the model 25 in that chambering to discourage them from taking the trouble to correct the error - so they dropped the chambering instead and some gun writers claimed that the cartridge was the problem. - A claim that T/C shooters soon put the lie to.
The original FN semi-auto in 5.7x28 functioned well and featured an innovative magazine system that was carried over for AR uppers, but the FN was prohibitively expensive, and from reports that I have read, it had accuracy issues. Many shooters are put off by its goofy appearance.
The 5.7x28 AR uppers have sold better than the FN, but not a whole lot better.
A flop as a military round, the 5.7x28 still is a step up from the ballistic twin .22 Hornet, which has short case life due to it's 19th century-design with paper-thin brass. The modern 5.7x28 case is much more robust, and so can be safely reloaded half again as many times as the expensive .22 Hornet brass. Once-fired 5.7x28 brass can often be found on the ground along with once-fired .223 brass at shooting ranges, but even if you have to buy factory ammo for the brass, it still comes out significantly less expensive than the .22 Hornet, most particularly if you reload.
The .22 Hornet has been around a very long time, and is chambered by a variety of gun-makers. There are a wide variety of .22 Hornet rifles to be had in bolt action and single-shot rifles. This creates a significant amount of inertia that, along with the widely-reported flop of the Savage model 25 in 5.7x28, and its lack of success as a military round has discouraged gun-makers from developing and offering 5.7x28 rifles that really ought to be taking us into the next century, giving the obsolete .22 Hornet case a rest at last.
The 22 TCM is meeting similar resistance, but for very different reasons. - A large number of companies, most major gun manufacturers in fact, have a lot invested in the .22 Hornet. How long will this inertia prevent us from moving forward to enjoy a more modern .22 Hornet equivalent?
Your guess is as good as mine.
In the mean-time, for the 5.7x28 our best bet for a competent and accurate hunting rifle today is the T/C Contender or Encore, outfitted with an aftermarket barrel.
The 5.7x28 case has some potential as a base for 5mm and 17 caliber wildcat cartridges. It make take a development in this direction to give the 5.7x28 the bump it needs to overcome inertia and begin to appear in a significant variety of sporting arms.
In any event, the writing is now on the wall for the obsolete 22 Hornet case. It is fated to a place along-side the 44-40, 38-40 etc. among the 19th century nostalgia cartridges that will be with us for a long time, but which have been superseded by more robust modern designs.