High end stereo preamps? Worth it?

I think there are...the question is related to return on investment.

I have a Moon DAC by Simaudio and they make impressive DACs that have preamp capability including MC/MM phone inputs as well.  My preamp is a McIntosh and they have quality DAC and Phono sections.

You can get a quality pre-amp with DAC and phono stages and you can even explore a quality integrated amp.  There's a trade off in costs and theirs advantages in simplicity including interconnectors and space requirements. 

A really good preamp is one of the most important parts of a system. I can still remember the first time I inserted a really good preamp, Air Tight ATC-1 into my system and being stunned at the transformation.

As others have suggested a good preamp doesn't have to be expensive, but they usually aren't cheap either. Buying used is always a good way to stretch your dollar.

There are always compromises to all in one designs.  For example my DAC has a 30 lb power supply, preamp separated power supply so all in ones don't compete.  That is not to say that all in ones cannot sound good.  The Vinnie Rossi all in one is a very good sounding unit but it is also a DHT design which is what I prefer.

Happy Listening.

Yes.

it depends on the room but if you’re good with the room, then yes for sure.

i went from Rotel preamp to rogue to Cary 98 then Cary 05 then arc 5se then finally audio research reference 40th anniversary.

the arc 40 is the best preamp I’ve ever owned and it’s hands down one of the best moves I’ve made.

How about the Benchmark (LA4)?   I didn’t see it on anyone’s list above, but I have heard a few good things about it personally. Just asking for opinions, I have no horse in this race.
— Jim