Upgrading phono stage

You really need to state what you are looking for.  So many times people want something "better" but never state what qualities they want that are lacking in their current gear.  So everyone chimes in with suggestions and again state is a given product is "better" but don't qualify their suggestion with useful info.  Sorry, just a pet peeve of mine.

Now with that out of the way, I have a little Bellari VP 129 that shocks me with what can be bought for under $300.  This unit is for MM only.  It is quiet.  The tonal quality is superb.  Rich and golden warm but not at the expense if detail or dynamics which are very good.  It's also super affordable to roll in premium quality tubes to tweak the sound.  I have a current production Mullard tube that is so good and have not yet rolled in the Tung Sol. (You can buy premium tubes that are tested AND listened to for an easy on the wallet price via Upscale)  

Used with Project Xpression table, Ortofon OM 20e Super, Sennheiser HD 660s.  (the headphone section is quite good as well on the Bellari)

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?

If you can find a used or demo Gold Note PH10 I think you will be impressed

Doesn't Rogue Audio have an upgrade program for the Sphinx?  Don't hold me to it, but I thought I read that the V3 phono was a good step up from the V2 version.  If you enjoy the Sphinx, I would look at upgrading to V3 as well your cartridge, a 2M Black or a high output MC (Dynavector, Hana, Benz Micro), whatever pairs well with your tonearm.

The Rogue Ares Magnum is a great sounding stage (and far better than any of their built-ins), but for only $1100 the Hagerman Trumpet MC actually beats it. I'd recommend stretching for that; it's possibly the last phono stage you'll ever need or want.