Audio Craft AC-4400 and related AC tonearms

Some notes, possibly obvious:
- AC3300 & AC4400 are later, more advanced models that command much higher prices (~3-5x) on the used market. I think they were manufactured until the early 2000s. 
- AC3000 & AC4000 are unipivots and AC3300 & AC4400 are "double point support", but I haven't seen one in detail, so I'm not sure what exactly that means.
- AC3300 & AC4400 have VTA on the fly, I believe, but the other features are similar. They all have adjustable silicon oil damping.

[Purely subjective assessment made with a limited number of cartridges and not in a fully controlled or blinded setting:] I have AC3000 & AC4000 and quite like them. They have an open, easy, refined sound compared for instance to FR64s which has a solid, full-bodied sound. I like having both and use AC4000 for chamber & choral music and FR64s for orchestral & jazz.

@sampsa55 very interesting, thanks Sampsa
I didn’t expect they were in production for such a long time, i thought AC3300 and AC4400 are from the late 80s. And yes, the price difference is huge compared to the AC3000 and AC4000 from the 70s.

Have you ever tried the FR66s if you like the FR64s ?
I will ask again, maybe you know better, what is the difference between the FR66s and 66FX (long versions)?
Maybe @nandric can comment on this subject ? 

Since the FR-7f and PMC-3 is what i use, i always wanted to try the FR or Ikeda tonearms with those carts. Currently i use re-wired Lustre GST-801 (discovery internal wires, zu audio mission mk2 with wbt rca’s) and the sound quality is stunning.

The AC3300 & AC4400 were in production for quite a long time. Here's a review of Platine Verdier from 2001 and it came with an AC4400, which looks to have been one of the recommend tonearms to go with the Verdier:
http://hifishack.com/jcv_platine_review.php

I'm very interested in the FR66s & FR66fx, but they are out of my budget... The difference, I believe, is the same as between FR64s & FR64fx: the former is stainless steel and the latter is aluminium. The anti-skating mechanisms are also different.

64fx or 66fx have lower effective mass than 64s or 66s, respectively. I think they are indeed made of aluminum . Otherwise, they appear to be identical to the s versions.

@lewm there is one thing i don't understand about those FX tonearms. They are black, the FR-7f is also black, they looks like they are made for each other, but the FX is lower mass tonearm.