What benefits to expect from tonearm upgrade

I have set up my system very carefully and that is why I commended as I did.An SME V didn't do it when I was experimenting,as well as other tonearms.When I "tuned" the sme's mass to match that of the rb300 and my cartridges, well, yes the V sounded closer to the rb and for me not worth the extra cost.A tonearm in itself does not sound good or bad,it is the good pairing with a cartridge that does the trick for me,as well as the phono preamp as I said earlier.
By these comments,I must say I do not underestimate any tonearm's qualities , low or high cost.

I agree with you Kiddman.

Gondo101, my experience was that images resolved into individual instruments, and there was no smearing. It was easy to follow the musical line from individual instruments. The difference between the Basis modified Rega arm and the Basis Vector arm on my Basis 2000 turntable, using a Shelter 901 cartridge was immediately noticeable and very significant. I was stunned because I did not think it would make a huge difference, but it did.

Some years ago I upgraded (so I thought) my resident cartridge for a well-reviewed and highly recommended replacement. What was all the fuss about the latter I wondered - it sounded dull and uninvolving on my RB300. The I upgraded the RB300 for a Michell Technoarm (a much modified Rega RB250) and immediately heard why the new cartridge was so highly regarded.

Moral of the story: upgrade your arm first and then select a good cartridge to match it.

Gondo101,
If you are happy as you say with your ortofon arm then a logical upgrade could be one of ortofon's own,or even Jelco's 12" versions.

Stringreen, you have not listened to the right arms then. There can be dramatic improvements.