My impression is that IKEA is so cheap because it is so global. In fact IKEA products and, maybe, Coca-Cola are the things you see ABSOLUTELY everywhere, so it's kind of a "global Walmart". (and it is actually quite comforting - when we were visiting some friends and relatives far-far away

for a couple of weeks when my son was 3, they asked if he needed anything special - we asked if they could get a little plastic stepstool from IKEA for the bathroom sink, and lo and behold when we arrived he had the same stepstool he has at home waiting for him on the opposite side of the world
For me when it comes to furniture IKEA is great for many kid's things (unless of course you plan on having a lot of kids and need your furniture to last decades), and that is the only particleboard furniture from IKEA that we have - since we really need it for very short time after all.
We do have a lot of their solid wood pieces, though (just counted 7 different HEMNES - no complaints so far

, several things for the bathrooms, and various smaller decorative pieces (lamps, mirrors, rugs, etc.) that easy to replace once you are tired of them (yes, great prices).
In general the same rule applies to IKEA things as to anything else: their more expensive things (and they do have quite expensive pieces of furniture, relatively speaking, of course) are MUCH better that the cheap ones. I'm always annoyed when a person goes to ikea and buys $30 bookcases and then complains everywhere that IKEA only sells crap: dude, why didn't you buy Stockholm bookcase in the first place then?
One thing about local IKEA stores: avoid Greenbelt IKEA on the weekends, especially on the "eat for free" weekends AT ALL COSTS!

It is a "United Nations" type of Zoo: literally people from every country in the world, and it is definitely not for the faint of heart. If you need to go to Greenbelt IKEA go on the weekdays, or better yet go to Woodbridge or Baltimore ones (although, they are smaller and don't have everything, but you can always check online the stock availability beforehand).