Just tried the new Zabu Zabu in San Mateo (it's been open for a few weeks now I think). I haven't been to the one in Berkeley, so can't compare - but I did enjoy my meal at the San Mateo location.
They have an all-you-can-eat option for $28. If you add $5 more, you can include appetizers (or alternatively, items from their grilled skewer section). There's a third option to get all 3, but they don't have the pricing for that yet.
Meat selections were wagyu, Australian lamb, beef tongue, and Kurobuta pork. It didn't say so, but I can only assume the wagyu is some hybrid and not actual wagyu. We tried the first three - all were very thinly sliced (a huge plus in my book). The wagyu was my primary focus - the first tray we got was very well marbled. The second two trays were less so, but still good. We got the traditional and sake miso broths - I found the traditional to be a little bland and preferred the sake miso one. Of course, you get your standard bowl of vegetables and choice of starch (rice, udon or ramen).
They were astonishingly fast at bringing us refills on whatever we asked for - the restaurant wan't busy, but I had always assumed places with AYCE would drag their feet with the refills.
Dessert was a scoop of strawberry ice cream - I was a huge fan because it was rock hard and slightly icy (I realize this might not appeal to everyone). Check came with two stick of gum too.
Ambiance was great as well - everything is very modern, spacious, and clean.