The first question that pops into mind is, are the 850s you are considering the Classic version or the Signature version (different crossover network). If they were purchased from the company within the last year and a half, they probably are the Signature version.
I have owned Axioms and now own Rockets (RS850 encores/RSC200 "Bigfoot"/RSS300s/RS250s). I still participate at both company forums.
I had the Axioms (M60s/VP150/QS8s) for a year, and my first impressions of the Rockets were colored by being accustomed to the Axiom sound. Had the situation been reversed, my opinion of the Axioms would have been colored by being used to the Rocket sound. I am one of those who does not subscribe to the concept of "speaker break-in." I believe what people refer to as break-in is actually the listener becoming accustomed to the sound of the speakers. Regardless, the end result is the same, and allowing some time to go by before making a final decision on whether or not you like a given speaker is a good idea. I've had the Rockets for 4+ years now and am very happy with them.
The M60s and RS850s are, for me, tough to qualify. I honestly like them both, and if I could only have one of them, I could easily be happy with either. Proponents of each brand will tell you the two speakers sound VERY different. I agree that there is a difference, but I don't find it as huge as others do. YMMV.
Axiom fans would describe this difference as "Axioms = accurate, Rockets = laid back." Rocket fans would describe the difference as "Axioms = forward, Rockets = accurate." The difference is basically the same, but they use terms to describe that difference which reflect their preference and are flattering to their favorite brand while unflattering to the competition.
There are positives and negatives to each side of this difference. I notice the difference most when listening to music. For HT, IMHO, they are both flawless. When playing a wonderfully recorded/mixed/mastered disc, the Axioms have a knock your socks off WOW factor. The 850s also have a WOW factor, just not quite as big as the M60s (only one sock gets knocked off
), but a "WOW" nonetheless.
On the other hand, when playing a less than ideally recorded disc, and there are all too many of these in existence, the Axioms will reveal all, and that disc will not sound very good (garbage in/garbage out). The 850s will be a bit more forgiving when playing poorly recorded/mixed/mastered discs. So, Axioms = big WOW factor/don't like lousy discs. Rockets = slightly smaller WOW factor (but still a "WOW")/more forgiving with lousy discs.
The 850s are stunningly beautiful, wood veneer, speakers. I have the now discontinued Macassar Ebony finish. The ones you are considering will likely be the more popular Rosewood finish. You can see my satin black M60s behind the 850.
While I don't feel the vinyl Axioms are bad looking at all, and was not ashamed, in the least, to have them in my living room, the wood veneered Rockets are drop dead" gorgeous." With the introduction of the wood veneered Axioms, that playing field has been leveled. I find the curved sides of the Rockets tastefully beautiful, and a bit more attractive than the angle-sided Axioms.
So, subjectively, the 850s satisfy my needs/wants more than the Axioms (YMMV) which is why I still own them. Haven't felt the urge to upgrade..............yet.
Please remember, each opinion you receive in answer to your question, including mine, is just that - merely someone else's opinion. There is no guarantee you will see/hear things the same way. What matters is YOUR
opinion. It all comes down to what you want, and which you would prefer.