As others have stated the guy who runs Royal Tiger Imports is the same person who ran I.O. that being Uli Wiegand. Though, the wording of the description makes it seem like the rifles were built by Childers and not RTI.
Even if Childers built them, and they generally do quite a good job building, it's still not a great value for what you're getting.
Kit builds are tricky and while I have kit builds, I won't have a kit built until I've had the chance to inspect the kit myself because it's such a toss up as to the condition of the kit and even if it's graded A++, the person who examined it may have missed something.
On top of that the rifle you linked to has a US made nitride barrel, and while those aren't necessarily bad, a cold hammer forged, chrome lined (CHF-CL) barrel is much preferable over a us made nitrided one.
A WASR underfolder is going for 949 right now on Atlantic Firearms and with a WASR-UF, you get a better barrel, as good if not better receiver, plus you'll be dealing with a much more reputable company in Atlantic Firearms vs RTI. I'd strongly prefer to buy from Atlantic because if there is an issue, they absolutely will take care of you. I have no idea what RTI's customer service is like, it may be good or bad, idk but I do know Atlantic's is great.