Trimaster was a new company that appeared during the 1990s "Hi-Tech Kit" boom that Gunze Sangyo started with their over the top Panther. Late war Luftwaffe aircraft in 1/48 were scarce back then, so Trimaster's kits caused quite a stir. At the time, the only fairly new tool subjects were from Volks in Japan. They had subjects like the Ar-234B, He-100D, He-162, He-219, and Ta-152. But they were all resin and quite expensive. When DML acquired the Trimaster molds, they did away with most if not all the white metal parts and tooled plastic replacements.
My personal experience with the Trimaster and later DML issue kits is that the white metal stuff was mostly gimmick, better served by plastic parts. The stainless steel photo-etch was a huge pain, as it was hard to find anything that could cut it. The injection plastic parts were very nice and surface details were really good...but the fit in a lot of the kits were so-so. But still, if you could get all the different materials to cooperate and join together to form a complete whole, you would have a great looking model of a (back then) unique subject.
Regarding value, I think the old kit market has changed over the years, probably due to molds constantly changing hands and new companies playing the retro reissue game. And while their kit subjects were unique back then, it is not so today. So personally I don't think an original Trimaster kit would go for much more than the original cost. But that's just my opinion.