choosing a tonearm for my new michell gyro

Hi everyone and thanks for the interesting answers. 
I have discussed my concerns with my dealer (which i trust), and we agreed that I will try the OL for a few months and in case I am not completely satisfied, I will return it to him and get a full refund/ new tonearm. 
So... The table was set with the OL zephyr.. 
I am in love (-: 
sounds great. I am glad I decided to take this chance. 

Audiomods is a superb adaption of the Rega Arm tube - and that's where all similarity stops.

This arm is a superb performer - but check it's compatibility to your cartridge first

Regards...

Why not a Michell Tecnoarm?

Do you have to buy the arm from the dealer?  If you can buy it somewhere else and have the dealer mount it, I would recommend an Audiomods arm.  Right in between the cost of the (2) arms you mention and way better than either.

http://www.audiomods.co.uk/completearms.html

Interesting he did not recommend the michell techno arm which is a modded Rega. I used the stock RB250 for years and i felt it matched well with the Gyro. My daughter is currently enjoying the table with the same arm i installed on in many years ago

No experience with the Jelco or OL on this deck. 

I had a gyrodec years ago but have never had any of those arms so I can't comment on which is the better arm. But if the reviews are controversial and the OL is priced much higher.
Why not get the Jelco, sell your old Project TT and the existing Rondo cartridge and upgrade to a superior cartridge? The cartridge plays a more vital role in how good your setup will sound IMO. I still remember what cartridge works well for me on that table.