How much difference will a phono stage upgrade make?

The op’s question is not so much is something better than the Manley - but if it will be a worthwhile and significant upgrade. IMHO when you have a jump in the price of a component you can and ought to expect a jump in sound quality as well - it may expose weaknesses elsewhere - and that’s a slippery road down (or is it up) the upgrade path. 
Perhaps you ought to ponder this. I have read review after review saying x is better than anything twice the price - yet at the next price point up they same the same thing about y - reviewers nonsense. In my experience a well matched more expensive is almost invariably better than a cheaper well matched component in a given set up - cables (in my set up) are the exception. 
So try and get a home audition and try the Manley out - try a few others and don’t get obsessed with topology and circuit - get what sounds good to you.

I think one of the best values in phonostages is the Pass Labs Xono.  It is a very underrated unit.  Works great with MC and MM cartridges and has a lot of flexibility when it comes to loading.  Fremer recently posted about this unit on his website Analog Planet.  He actaully said he believed it to be one of the best at the time.  It's a great unit and Pass has great support.

12hz, before you start dropping coin on a new phono stage, you may want to look at the load resistors in your current model. Replace them with Vishay foils and you will be shocked at the reduction in noise, and improvement in low level detail without changing the frequency balance.

would agree with photon46, spending a lot more does not mean better. Have dropped 6K on a phono stage only to find out it was not as good as what I had.

the EAR 834s (real and clones) are also really good.

J

@12hz - it's been 6 months now, did you end up with the Chinook? If so, how are you liking it over your previous stage?

Also, was curious if you gave any thought to one of the E-Glo stages from EAT - since you could then share their Linear Power Supply for the phono stage with your C-Sharp? I'm currently considering this setup myself, as I also have the C-Sharp...

Thanks

12hz, this is a sideways answer to your interest in the Chinook.

I owned a Manley Jumbo Shrimp and Snapper amps for a couple of years.  I was very pleased with the sonics of both but a problem developed with unstable bias in one amp.  I lived in SoCal then and ended up taking the amp to the factory for repair.  It was a weird problem to diagnose and required two tries, but I was still pleased by how fairly they treated me (it was out of warranty).  

Also I was able to take their factory tour twice and I was quite impressed by their operation.  Also I've spoken with EveAnna a few times and enjoyed her enthusiasm and knowledge.

I do not have direct experience in auditioning the Chinook, but have no hesitancy in recommending Manley products.  I believe they are a first rate company.

I will also say I've auditioned Herron electronics at shows and a friend's system, as well as talking with Keith.  I've been impressed by him and his products as well and endorse them if they fit one's budget.