Coming in a little late on this..... Yes the MPI stuff is pretty awful. I admit though, at my first Fest (03) I did pick up the music box, but I think the only other stuff I picked up that time was bookmarks and all the zines I could grab (course non of THOSE came from MPI).
The issues with the plates sound typical of most "official" merchandise since I've been in fandom, with the tchachkes from Paramount and Lucasfilm not being anything to write home about either. That said, I did get a couple bobbleheads over the last few years, the ones that looked GOOD -- and also picked up the Majestic Quentin doll (Barn was already sold out when I got to their table in 06).
By and large, the official licensees seldom, if ever, GET IT as to what fans are about and what we want in the way of toys and collectables. Its on a level with the management at SCIFI when they were trying to get off the ground and were making the rounds of local fan groups. They were consistantly shocked that the large area fan clubs (the one I was an officer for at that time was Dr.Who/Blakes 7 and is now much smaller, but includes all SF media) were NOT run by the pimple faced 15 year olds with no girlfriends that SciFi Buzz showed they thought was the average SF fan. Unfortunately they seem to have trouble understanding that the adult fans who have the discretionary income to buy the pricier items DON'T want Junk. They are smart enough and accustomed enough to purchasing decisions to want value for money.
Thats a large reason why, no matter how much heat licencees may or may not put on "unauthorized" fan produced merchandise to try and make it go away, those are the products most fans prefer to spend their money on. Stuff produced by fans for fans is usually produced to a higher production standard, as well as being better targeted to what the fans of a specific show or movie might actually WANT.
Jeannie