Upgrading phono stage

@mijostyn I appreciate the feedback. I have been wavering between going to a 2M Bronze or a Nagaoka MP 200. The soundsmith Othello ES is of interest too. I wasn't sure if I will get more bang for my buck with a cartridge or phono stage. Right now I don't have a dedicated room for listening. Due to space and practicality seperates are not an option right now. I could actually do a cartridge and phone stage if it comes in under $2500. Any opinions on those cartridges or any other suggested ones?

So much great info and I appreciate all the responses. It is a little hard for me to say what I am looking for other then "better".

When I upgraded from my Onkyo receiver to the Rogue I was blown away by the sound quality and warmth of the class D compared to the Onkyo.

When I went from the $100 audio techica cartridge to the Ortofon 2M blue I was impressed at the increased Soundstage and "real" life feel comparatively.

When I rebuilt my Epicure M-150's it was like I was hearing a quality in the music I had not heard before.

When I switched in my new to me KEF 104/2's I was hearing instruments and notes I didn't know were on tracks I have been listening to for 20 years.

I dont know if I could have told you what I was looking for other then better and more of a "sitting in front of the band experience". So far all of these changes have been truly moving and I find myself reaching for a record rather then the TV controller more then ever. I am certainly happy with my humble setup. I know there is more out there. I like the idea of experiencing incremental changes. Sure I could spend $20,000 on a set up that should be the "last" set up but..... I am really enjoying slowly evolving. Not sure if that makes sense. 

Rather then asking for specific brands. Will  a outboard phono stage costing $1500 or less be better then the onboard in the Sphinx or should I upgrade the 2M blue to a cartridge in the $500 range. Where will I achieve the more impressive jump?