opinions about leaving Audio Technia ART-9 MC for a Ortofon Cadenza bronze mc ?

bronze is a great cartridge

Either cartridge is fantastic.

I changed from Art-9 to Aidas PanzerHolz Diamond last year, the difference is significant in all areas, I think this cart performs well in the 5K league at under 2k. You could consider this also as it will outperform the Bronze too..

Going from an ART-9 to a Cadenza Bronze might very well be a lateral move at best. You really have to A/B them against each other to know which suits your tastes better.

Choosing a cartridge from what someone else tells you vs. live listening is fraught with danger. As an example, VPI told me what a great cartridge the Grado Gold was when I inquired about buying my (gen.1) Traveler so I took their word for it and placed my order. Much to my dismay I found the Grado to be the most boring cartridge that I ever listened to. 

A lesson learned!

Cheers,
              SB

I have two VPI Prime Signature turntables. I have had the following carts on them:

Koetsu Vermillion
Koetsu Rosewood Signature Platinum
Cardas Benz Silver Ruby 3
Van den Hul Crimson 
Van den Hul Colibri Stradivarius 

I can say that you will need an excellent cartridge to ever be satisfied with your turntable.  While the Koetsu carts are very mellow
they simply cannot compete with the Van den Huls. The Cardas Benz is very good but again not as good as the Van den Hul. In your price range I think a used Crimson would work very well.
The VPI arm is well suited to it.  Several are for sale on Audiogon.

Hope this helps.

BTW, I am in no way associated with any of these firms.