Well, in my experiences so far with some cheap Chinese ARF's. They do work OK but  the instructions are essentially worthless. usually the instructions are a mix from several different models and poorly translated at best.
So you need some experience in how to build a ARF without instructions. When you buy a more expensive ARF from a brand name company, they include really good instructions and details on how to build the plane. Plus all the parts they include work on the plane too.  About the only thing on a name brand ARF that I change is to use a throttle cable instead. I also like to use the Dubro EZ-Links too in places. Quality control may also be hap-hazard, one plane may be Ok and the next a piece of junk.

The parts may or may not fit in with the plane correctly. So you need to plan on buying extra stuff. For example, the landing gear axles threaded shaft were too short for the fiberglass landing gear struts on one of my ARFs.  I substituted better threaded 1/16" pushrods as the metric push rods that came with the kit, did not match the clevises. I also used a throttle cable instead of the metric pushrod. The motor mount was Ok, but too short for my engine, so i needed to get another motor mount that was longer. Screws may or may not match up either. it is almost like getting the wrong parts package with the kit.

Since I have had wings fold in the past on a couple of ARFs (now this was after quite a few flights though), I opted to use some fiberglass tape and epoxy the wing center section as a additional precaution. Check the landing gear area to ensure it looks stable and add more glue as needed.

Also if you get a damaged or defective plane from the cheap shipper, it is usually too bad, bad luck, thus little to no support from them. But from a big dealer liker Tower Hobbies or Hobby-Lobby, etc. You can get replacement parts, warranty service and even assemby questions can be answered if you have problems.

So it is a question of what you consider important.
I would trust a dealer like www.nitroplanes.com a lot more than Ebay. The Ebay dealers may be trying to make a fast buck off of reject or defective merchandise. but you have no way to know for sure.