Logical cartridge upgrade for a long time Shure M44-7 user

Thank you all for the suggestions, lots of directions to go in. I really appreciate it. 

@yogiboy I've played around with some JICO replacements for the M44-7. While they will totally pass in a DJ booth setting, at home they fall short, with a distinctly duller, woodier sound. 

@chakster Thank you for the suggestions, will look into them. I wrote to Jico about the SAS option, and they said they don't make one for M44-7.
@jjss49 thank you, will look into your suggestions. Re: Nags, I just read way too much hype before trying it, I think it messed with my expectations. 

Thank you all for your recommendations. 

@nickpish I'm usually slow moving with pulling the trigger on upgrades etc., so it may be a while. But I do always try to come back to threads to give an update for due diligence. Great to see someone else trying to figure out their next move past the M44. 

@atmasphere Wow. Thanks for that info. It's funny - while my ears have gotten quite used to M44, I always assumed that some of the distortion I hear (probably around 8 - 12Khz range) was due to other factors in my system. This makes a lot of sense.

I don't have a lot of experience with different cartridges, but I've had a hard time fully buying into the 'musical' descriptor for a lot of components, including carts. I feel like it's often used to justify muffled, dull characteristics. If I know for fact that Stuart Staples' singing on Tindersticks albums include a subtle but always recognizably breathy, throat-y texture (years of smoking + whiskey?), and I'm used to hearing that clearly while a cartridge like Nagaoka completely fails to extract that from the vinyl, it's hard for me to buy into the idea of it being more 'musical'. I'd say the opposite. Thanks for the recommendations and knowledge, really appreciate it!

@nickpish - since my post, I went with an AT VM540ML based on the recommendations here. I don't want to sound like a confirmation-biased fanatic, but man.. the improvement has been incredible, even right out of the box. 
Much clearer details across the whole spectrum. 
Sonic details extracted that weren't available before with the M44-7.
Inner groove distortion gone for the most part. 
The 11khz 'peak' mentioned by @atmasphere makes a lot of sense now. I used to think that was a given with vinyl, but with the AT upgrade I feel like I have access to the full frequency range without distortion...
And just overall coherence, detail, and what I would call a more 'physical' listening experience. 

Specifically about bass: I don't think the VM540ML is MISSING much bass per se.. It's definitely not an M44-7 in sheer bass output.. it's a bit more subdued, but again to @atmasphere 's point, I do feel like the bass that's getting reproduced is more in line with what was intended, rather than what was made up by M44-7. Right out of the box, the initial feeling is that the bass sounds a bit 'woodier', slightly dull on some records. But even with about 20+ hours of burn-in, I'm already not really missing M44-7. If you have a decent phono stage, and somewhat capable speakers, I'm pretty sure the AT won't disappoint in the bass department. 

Also, I'm confident in my analysis, because I have tried other carts before the AT, unlike the Nagaoka MP110, and this is a completely different experience. 
Also to note - if you get the MV540ML new, and pre-installed on a AT headshell, it's more of less optimized for an SL1200 table (I find). I had to do very minimal adjustments to get it to sound great, track nicely, and extract all the sound I was missing properly from the first moment til the end of a record. 

@nickpish As you mentioned, it's nearly impossible to come to a universally accepted definition of descriptors, including 'brightness'. To me VM540ML sounds more detailed, with more information extracted especially in the high registers, and most importantly without distortion. 

As I mentioned in one of my previous post, I'm also skeptical of some of the descriptors where lack of detail, and a darker, dead-er sound is described as 'musical'. To me there is nothing 'musical' about lack of detail. In the same vain, there is nothing excessively 'bright' about the increased detail in the high registers, which I experienced with VM540ML. But then, that argument gets us back to atmasphere's point about whether you have access to master tape, and really know how something was meant to sound in the studio. And that's where I jump off the audiophile ship :)

Congrats, @nickpish. I have a feeling you will enjoy the upgrade as I did. 
In terms of budget friendly phono stages, I've heard nothing but good things about the Schiit Mani, performing way above its 'pay grade'.