Just back (yesterday) from both Akellare and Arzak (also the Gehry in Elciego). In short, while the food is comparable, Akellare has Arzak beat in the service department. A few issues with Arzak:
we sat for 15 minutes before the sommellier brought us a wine list - it then took him 15 minutes to return;
there was a service door beside our table and all of the staff were in there making a huge racket; - there should be no "bad" table in a restaurant charging 140 euros per person.
there is very little english spoken (at least that night) so it is very hard to understand what you are being served;
there are a LOT of smokers there - while we don't care that much - it does spoil the food;
Arzak was very good, inventive and really a nice experience. We did not experience anything negative at Akelarre - service is spot on and they provided an english speaking waiter. cost was 125 euros and worth every penny.
Gehry was also great - fabulous location, high end design with food and service to match. There was one course that I found disappointing (tuna was tough) but everything else was spectacular. It was quite a bit cheaper than Akellare and Arzak but it will be up there soon. We ate in the modern, not the traditional.
Also ate at Eschaurren - very, very good traditional food.