Hi mittensam, I've been to extebarri and akellare ...
Extebarri lunch ala carte shared 1 serving of each of the following - chorizo, smoked butter, oysters, palamos prawns, squid, cheese flan - 3 glasses of wine, a bottle of water n a coffee - bout euro 180
Akellare lunch - w different tasting menus (one w wine pairing) 9 courses each, additional 2 glasses of wine, 2 bottles of water, 1 coffee - euro 430
Of the two, akellare has of course t better service, great selection of wine and a spectacular view. However food at extebarri wins hands down - the Tasting notes here were prolly the highest during our 4 day trip to barca n San se. I would not go back again to akellare, extebarri I want to bring my parents and my best friends to ...
Etxebarri is definitely more homely. I tried to buy their chorizo (which is home made and if you ask me probably the best and freshest I've tasted in Spain) but was unsuccessful. Percebes were also excellent and we had a fun time opening them up and learning how to eat them.
Akellare is definitely more refined, a place you would take people for a more formal occasion. The views of the sea are amazing and the dishes are more inventive and playful.
They are all brilliant but very different. Mugaritz is the restaurant which you are most likely to come away from disappointed but it is also probably the one you are most likely to be blown away by - opinions go all over the charts.
All Michelin up to date prices are on the ViaMichelin website. Mugaritz is 150 euros.
Update to the last post: My husband and I went to Etxebarri two days ago and had the most amazing home made chorizo as well as a few other dishes like gambas and percebes. Simply made but oh so good. Cheaper than Mugaritz and Akellare and the wine is way more local focused and cheaper than the other restaurants. It is a pain in the ass to get there so I'd recommend a gps and giving yourself about an hour and a half to get there.
Mugaritz is my favorite restaurant in San Sebastian. The level of detail in their dishes as well as the presentation is awesome. The staff speak everything from French to Spanish to English to Greek so it's easy to communicate what you like, your allergies, etc.
The chef likes to use every part of the animal in different dishes. This month for example, is game season, so they had things like guinneahen, pigeon, hare, etc. and cooked not only the meat but also incorporated other parts into the dishes. You could have pigeon moose in a macaroon that looked like dessert but was actually salty (yum!), then have game broth in a later dish. All of these animals sound weird I'm sure, but the dishes and the presentation were amazing. I've been many times and each time I try to go during a different season so I can try different meats/veggies/etc.
Also, their sommelier, Nico, is super nice and selects wine all the time that is in everyone's price range. I had a La Tache there once and it was AMAZING! They do not try to make huge profits with their wine selection, which enables the customers to try good wines at good prices. For example, you can purchase an RDC for 500 euro there which you will pay upwards of $2500 in NYC (which is where I'm from). Or, you can purchase a fabulous Rioja for 150 euros if you prefer, there is something for everyone. Pre-fix menu is approx. 175 euros per person and you get about 20 dishes if I remember correctly. Well worth it.
Just to add to Citykid's post Nico is probably the best and nicest sommelier I have encountered anywhere in the world and the value on the Mugaritz wine list is frankly ridiculous for anyone used to London/NY markups. We had a bottle of 2001 Alion which was cheaper in the restaurant than you can buy from a shop in London.
The next day we were eating lunch in SS and Nico and two colleagues spotted us and came up and had a chat about the meal and gave us some more tips for the city. Definitely beyond the call of duty.
For a real foodie, travelling with foodies - go to Mugaritz 100%.
If you have a wife/husband/companion who goes along with you but doesn't enjoy food in the same way then Akelare is probably the best choice. We loved both.
Akelarre for lunch a couple of month's back was around 160 euros for the tasting menu. Etxebarri was 130 and I haven't been to Mugaritz for a couple of years so I can't comment. All three are excellent, Magritz pushes the boundaries the most but has a few misses, Akelarre is quite brilliant, with cutting edge food, a great wine list and excellent service. Etxebarri is a nightmare to find, the service is a little haphazard and wine list is weak but the food has an incredible purity and I would go back in a heartbeat.