The thing that always struck me about these bikes was the amazing value. I bought an MT700 frame around 2007, painted and built it with new and used parts off ebay for way too much $$. It was one of the smoothest riding bikes I have ridden, but it was stolen after a year, so I started looking for a 750 in my size. It took a few years of haunting the local CL listings, but I finally scored with this '97 model. The 21" frame is a bit large, so I got a VO "Postino" bar and moved my hand position back.
I'm not a bike historian, but I don't think there were too many models of bike that could be used for the "adventure touring" type of riding when this line came out in 1990. The MSRP for the 750's in the day was under $600, when the Trek 520 was going for $1000. Many people did fit them as touring bikes.