I had an RAR LR Target, sold it and upgraded to the CZ 457 varmint chassis 16".
RAR Pros:
Takes 10/22 mags that are readily available and hold 10 rounds flush fit
Like you said, ready out of the box. Not much tinkering needed
Cons:
Not nearly as accurate as the 457
Trigger is "ok" but has a good amount of creep. You can take the spring out to get it pretty light but can't eliminate the mush
Aftermarket support is almost non existent. I think the barrel is pressed in (could be wrong) so barrels are not available
The machine work on the bolt was pretty rough and mine did not cycle very smoothly, although it was very reliable in feeding and extracting
Overall the 457 is a much more capable platform. Wide aftermarket support for stocks, chassis, barrels, scope bases, and triggers. Although the factory 457 trigger is amazing and I have not considered replacing it after tuning. Super smooth action, very accurate with the factory barrel. The only thing I don't like about the 457 is magazine pricing and availability and the fact that the 10 rounders are not flush fit. Overall I am extremely pleased with my 457 and do not regret selling the RAR.