Looking for the best moving coil cart that is around $5K used

Also, I agree with the folks - TT quality is a factor.

I did a similar thing. I disregarded expert advice, and spent on cartridge, tonearm, and turntable, in that order. It was a mistake on so many levels.

First, a TT gives you more bang for the buck. A better TT should give you less noise, less sibilance, more clarity, etc. If it doesn't, then something is wrong, probably setup. Very few people do it right; for example, how repeatable are the settings of the torque screwdriver that your expert uses? (German units don't drift; much).

And that's just one of dozens of potential issues. Ever wonder how far off the perpendicular the stylus and cantilever are? (Even my higher end  Koetsu is off). Well, that's why you need azimuth adjustment. Stable azimuth adjustment.

Second, cartridges wear out. Only a factory rebuild preserves the house sound, at least at the level you are considering. With a defective tonearm, that could be unnecessarily frequent. Think more dollars every so often, whereas TT do not wear out. Nor do tonearms. A good tonearm will retain its settings, whereas some tonearms will not even allow the necessary adjustments in the first place. Which may be the source of your discontent.

So I suggest that, if the mass market stuff doesn't work for you, try something else. Consider Trans-Fi. I understand that their mag-lev TT is something else; I know that their air bearing tonearm is something else, as I have two of them. ($1000 each - what a bargain!) All within your budget, if you buy from the factory. Google them.

Good luck.

As others have said, TT is a big factor in the final sound, as is the arm, but for carts you must look into the Aidas Panzerholz Diamond cart. It is quite simply the best value cart available at the moment, and selling at under $2k, it compete's with carts $5-7K+. I took a punt and it paid off, bought from Agon seller gr audio. Replaced an ART-9 and beat it across the board so conclusively I sold the ART-9 the next week, if I needed a spare cart I'll buy another Aidas..

Years ago I happened to be be at a high end hi fi shop in the bay area one day when a person was trying to make a decision about which turntable to buy. The contenders were a Linn Sondek and a Linn Basik. Both tables had the same arm and both were equipped with the same cart - I think it was a Grace F9E.

First up the was the Axis and it sounded good, but within seconds of the Sondek starting to play it was no contest. The Sondek was clearly better. I was actually stunned by the amount of the difference.

Now, to be fair, there are numerous variables that could have been tweaked by the dealer to make the Sondek sound better, so all this has to be taken with a grain of salt, nonetheless the difference was startling.

I have just acquired a Shelter 901 Mk III and loving it, but I don't have near the exposure to high end carts that others on this thread do.

I'll weigh in with a few terse comments:

1. Setup is  the weak link in the vast majority of turntables/Tonearms/cart.
2. As used cartridge is an unknown, and at best has only a portion of its life left - not just the tip, the suspension
3. I have not had that Pioneer, bu if its up to the challenge that you must pose with a $5k cart, its a bloody miracle.  See setup above.
4. Note that TTs are primarily about reducing motor noise and speed variation; tonearms however are more than good/bad - the mass-to-cartridge compliance matching becomes critical - just liek springs and dampers on a race car.