Have a U-Turn turntable with Ortofon 2M Red cartridge. Upgrade cartridge or turntable???

@chakster I'm not sure why you keep recommending cartridges that aren't in production and nearly impossible to find.  

You'll get more bang for the buck upgrading the turntable.  Consider buying used.  Try going a little higher in the Music Hall line, like a MMF-7X or 5X.  I haven't heard the Classic, but it looks like a decent enough table if you prefer to buy new.  It should be an incrememtal step up.

You might be able to find a decent used table with an OK cartridge at your budget and then you can upgrade the cartridge later.

If the turntable itself has issues adding a better cartridge won't make them go away.  I'd rather put an inexpensive cartridge on a good turntable than a good cartridge on an inexpensive turntable.  It all matters, but the turntable is the foundation.

How long have you had the cartridge?  

I am not a fan of the U-Turn table, but I am not sure I would go for a Music Hall either. There isn't anything about it that stands out that defines it as a quality turntable. Personally? I would find a nice demo, open box, or even pre owned Rega and start with that. If you went pre owned I would budget in an upgrade for a Tango sub platter in the future and you would have a nice bang for the buck table. 

As far as the Denon cartridge goes, I would think that is a fine upgrade over the Ortofon Red. The Red is a polarizing cartridge, there are many people who find it too aggressive and unrefined. The 110 is a tried and true budget cartridge, with a good quality diamond on it for the price. If you shop carefully on the net it can be had for under $300. It being HOMC is not a bad thing, while LOMC is technically better, there are many well built HOMC cartridges out there, the Denon is one of them. One caveat though. Its output level is not as strong as many MM or MI cartridges, so be prepared to have to turn the volume up a bit higher than what you currently do. 

Other cartridge alternatives are from the Audio Technica line. The VM540ML is getting good feedback from owners. I also hear of folks taking the 95 body and putting the LP Gear Vividline stylus on it and getting very nice sound for the money. These are good choices also. 

But audio is an adventure! There are many pathways to good sound, and all of us have different things we want to hear. Best of luck with your journey. 

@big_greg

@chakster I’m not sure why you keep recommending cartridges that aren’t in production and nearly impossible to find.

I feel your pain Greg, but they are not "impossible to find", those two models i have mentioned are for sale on ebay very often from many different sellers in USA or EU, even NOS samples.

If you don’t search you will not find, but if you do then you will find and it’s not a big deal. I managed to buy them all, nearly all Stanton and Pickering line (top upper 5 models of each brand).

If you’re in USA then it’s first brand to search for, because you can find local dead stock and stuff like that for very low price (almost nothing), ebay prices are higher for sure, i have mentioned ebay prices (and other sources like UK Audio Mart of US Audio Mart are very helpful.

I recommend them because i like the sound so much!

Maybe you’re not looking for some NOS cartridges, but i’m sure you are aware of NOS tubes and NIB are still available even if they are from the 30’s like some tubes i bought for my amp this year.

Regarding rare cartridge you can simply ask me if you can’t find them yourself.

Remember those endless Mm thread and seems like everyone was able to find many top class vintage cartridges (even in NOS, sealed boxes).

I have a Stanton 981 HZS cartridge that came with a JVC turntable I bought.  It didn't sound that great, but I think the stylus was worn and of course, an original replacement is also unobtanium.

I also like the Rega recommendation and just move up the Ortofon line or consider a Nakagoka MP-110 ( $165 )