Particularly the Solid State path. EQ is very clean and compressor is fast enough to deal with dynamic issues when tracking. I also like the Mic pre on vocals in particular, combined with a C12-A for example.
The tube path is also good, but benefits from replacing the stock Sovteks with Telefunkens (which Millennia will do, or you can do yourself). Just gives it a tad more warmth, which makes it a more useful alternative.
I'm yet to find an all-in-one type tracking channel I prefer.
I have used both of these units, the 737 and the STT-1. I like the Millenia piece much better. Among the highlights: much more versatile with the option to switch in and out the tubes in different sections: IE the tube circuit can be switched in for the compressor, but the EQ solid state; it has a de-esser; the eq sounds good, each band can be switched in/out. I have used with a U87 and a Soundelux U99, which, despite all the tubes and potential for mudiness, sounded very smooth.
The STT-1 is great. How much $$$ is it worth in your package???
Resale would be $1800 up (maybe $2k?). I don't know, but that's the ballpark. I've seen people try to sell 'em for more on craigslist, but they keep being repeat-listed, so I assume they're not selling at higher prices. It's hard to tell 'cause it's not exactly a common piece.
It sounds great with a Pearlman mic for guy voices, girl voices, and acoustic guitars, I will say that. But, then again, for that kind of $$$, it had BETTER sound good...
It has a rep for being 'neutral' when it comes to tone-color. I would tend to agree.
Millenia STT1 is a great piece of gear. The solid path is without comparison as far as clean recording goes (acoustic guitars e.g.) For the tubes path I would advise changing the tubes to Telefunken ones. Not that the original ones are bad, but the Telefunken ones give you a really noticeable second choice as compared to the solid path.