Well, I'm not really "dumping" on them, just relating my particular experience with one of their big bomber kits.
Revell Monogram do have certain things going in their favour, one of those things is that from standpoints of affordability, popular subject matter and sheer longevity as a brand in the hobby; they are very accesible to many modelers from beginner all the way to master.
I remember when, if you wanted a 1/48 F-14 Tomcat, the Monogram kit was it, no one else made one at the time it was new. I remember when they released it in full colour VF-111 "Sundowners" markings. Man, did that thing stand out on my shelf! I've heard people dumping on that kit, and yes it's easy to do with Hasegawa and Tamiya Tomcats prowling the hobby shop shelves with their sharp recessed panel lines and framing quality box artwork and price tags easily double the Monogram kit's cost; but I have many happy memories of that Tomcat from Monogram.
The Memory that really sticks out is the cockpit. It was unbelievably detailed for a kit at the time, gorgeous relief detail on the consoles, beautiful multi piece ejection seats...
My very first kit was a Monogram SnapFast 1/72 F-4 Phantom that I built when I was seven years old (I hit 32 this coming August) I "flew" many missions in the living room with that Phantom and exucuted manuevers with it that would probably make a pilot of a real Phantom air sick :-) Well, I brought her in for one too many hard landings when I was 10, but that was O.K. I'd built my first model and had a blast with it beyond the building of it.
I can't fairly dump on them, but I concede that if you've got the money, you can do better. If you don't. it's good to know they're there so you can still have access to the hobby.