Zuma sets a new standard for Japanese, while Orso is an Italian disappointment

Restaurants where the beautiful people hang out are always expensive, usually easy on the eye, but not necessarily guaranteed to give you a remarkable meal. I remember being distinctly disappointed a few years ago when I took a reporter to Nobu, famous for ... amongst other things ... Boris Becker's love tryst in the broom closet. The food was good, but on par with sushi I'd had in other places. The difference was the outrageously beautiful presentation and a feeling that you might see someone famous at any moment. Which was not enough to justify the breath taking prices.

Thus I approached a lunch date at Zuma on Monday with moderate expectations. It is the new Nobu: Japanese, elegant, in a posh part of town (in this case in a backstreet across the road from Harrods), patronised by the rich and famous. A sure sign of a "beautiful people" restaurant is when a Google image search turns up more photos of famous types at the place than of the place itself, as is the case here. There were plenty of buff bodies, high cheekbones and designer clothes on our visit, but I didn't pay much attention. I was far too captivated by the magnificent food.

We ate as the menu recommends, selecting a variety of dishes and sharing. This seemed particularly appropriate as we were seated in the bar in low, comfortable leather chairs gathered around a high coffee table. It felt more like a living room than a restaurant, especially given the stone walls and subtlety of design.

We started with a variety of sushi; without doubt the best I've ever had. The rice was slightly warm, perfectly sticky, light and flavourful. A meal on its own, made better by the strips of raw fish so fresh and buttery they melted in the mouth. Other shared dishes included their justifiably famous black cod, deep fried chili squid (surprisingly delicate for what's often a greasy dish) and a kobe beef fillet that was the best red meat I've had in a very long time. All this was washed down with tiny glasses of peach sake, the fruity richness of which was a perfect complement to the strong flavours of the meal.

Evidently Zuma has one of the widest sake selections in the UK and its waiters are experts. My host had been here before, so he was already clued in to the peach sake secret. I'm not sure I'll ever be able to have sushi again without wanting a glass.

Later in the week I was faced with the challenge of taking a colleague for dinner without booking in advance ... something I should never do. We headed for Covent Garden, which probably has a higher restaurant density than anywhere in London. Sadly, I have yet to find anyplace I really love in this tourist-packed district.

We popped into Orso, a long-established Italian place I'd eaten at years ago. Its convenient location and broad, authentically Italian menu are a good start, but the service is horrific and the food deeply average.

We waited nearly half an hour to have our order taken; this in an almost empty restaurant with at least five waiters on duty, all milling about near us and sometimes making eye contact, but never coming over. I was starting to wonder if something had gone badly wrong in the kitchen and the staff had been told to buy time by ignoring the customers. Fortunately they had brought us a bottle of red wine, I was getting to know an interesting new colleague and had nowhere else to be, so I let them take their time.

My starter should have been exceptional: veal and bufala mozzarella ravioli. But the pasta was a bit too dense, the meat stringy and the red sauce a bit too close to a tin of chopped tomatoes with nothing done to them. All made worse by the fact that the ravioli were lukewarm and cooling when they got to me. My main course of chicken breast was overcooked and rubbery, making the best part of the meal the baked aubergine (eggplant) and sauteed spinach in the side dishes.

Thus it looks like I will continue my search for a mid-priced, mid-town Italian restaurant that satisfies my tough standards. But if I'm looking for Japanese? Zuma's worth the trek across town to Knightsbridge.