I do not consider myself to be an absolute expert on RTA kitchen cabinets but from what I do know there is definitely a distinct difference between high quality and low quality RTA cabinets.
Nowadays, all RTA kitchen cabinets should come with easy installation directions, all pre-drilled, and really the only tool you should need is a screwdriver (for CAM lock systems*).
If you are looking at RTA cabinets that do not have those features than you are wasting your time (in my opinion).
People who buy RTA Kitchen Cabinets know that they will have to do work to assemble the product and should be looking for high quality easy to assemble kitchen cabinets.
Construction of ready to assemble kitchen cabinets should be the most important thing to consider when purchasing your new kitchen.
For starters, do not ever buy anything that has particle board or 'fake' wood in its construction, you are asking for a problem if you do.
Particle board is constructed of wood chips, saw dust, and other wood particles and is less dense.
It can mold, warp, break, and is a huge no-no when considering what RTA cabinets to purchase.
Solid wood fronts is your best bet.
Now, if you want complete solid wood cabinets you may have to get them custom built and as far as I know they are not available as RTA.
You should be looking to purchase 100% solid wood fronts and sides (door frames) with plywood backs and bottoms.
The thicker the plywood, the better.
A good thickness is about 1/2" for both.
RTA kitchen cabinets are becoming more and more popular everyday, as consumers become more cost effective and realize they can get the same quality kitchen cabinets for a fraction of the cost.
*CAM lock systems - consist of a base and a cam that latch together.
Basically, you put the two pieces of the cabinet together and screw the cam with a simple turn and it latches the cabinet together.
A CAM lock system is one of the most sturdy assembly systems you can buy.