Phono Stages with External Power Supplies...Worth It?

It all depends. With both preamps and phono stages, separating the PSU from the line circuitry is in theory optimal. Let me emphasize in "THEORY". This is because there are phono stages and preamps with built-in transformers and capacitors (PSU's) that are superior to others that have separate with the PSU tied to the line stage via umbilical. Separating the boxes is expensive. So the short answer is that with anything less than state of the art, you are generally better off with a one box solution but not always. Generally. My Manley Steelhead has a separate PSU but there are likely (scratch that, definitely) better phono stages that are one-box. My ARC Ref 6 preamp is one-box but there is little or nothing on this planet (IMveryHO) that beats it. But then, there is the Ref 10 that sounds different, but not necessarily better. 

@fsonicsmith that makes perfect sense. Thsnks

@stereo5 I’ve yet to run across anyone NOT running the reference version. It’s not a money issue as my budget is $2k it’s more that I’ll be downsizing to studio apartments when I get empty nested so I’m trying to have my endgame system not have 27 boxes.  Part of me thinks to skip on the reference and go with the standard to then make my stereo Khartago into monos. 

fsonicsmith, I am surprised you would place the AR Ref6 above the Steelhead, but if you are a "solder slinger", like me, I can suggest some very small changes to the Steelhead that make it sound worlds better.  Either PM me or indicate here if you want the information and my suggestions.

gochurchgo, Sounds like you want emotional support for the decision to do without the external PS, which seems to be your preference, not based on performance but on space allocation, which is fine.  Someone else pointed out that you can always "upgrade" to the external supply at a later date, if you should feel you need it.  That sounds like the "win-win" solution for your particular needs.

@lewm incorrect. Merely asking for thoughts on external power supplies in a general sense

I'd suggest buy it sans PS and see how you like it. The real question is, will you always wonder?