Having checked into the Hilton I was looking forward to a break from the usual LHR hotel food and was therefore excited at the prospect of Asian food. My expectations were clearly too high. Should have walked away when three wait staff saw me waiting to be seated and yet chose to ignore me; instead waiting for the restaurant manager to greet and seat me. I ordered the tempura. It was the worst tempura that i had ever tasted - bland, too much batter. I've clearly been spoiled eating in my home town of San Francisco. Next was the beef and basil; another favourite of mine. Better than the tempura but the beef was overcooked. With a glass of wine the total bill came to 38 pounds; they had the audacity to add a 5 pound service charge. Overall a disappointing experience and one that I wouldn't repeat.

Travelling alone normally means an average table, but I was given one with a good view of the restaurant for people watching! Food and service is excellent and even though it is an airport hotel, I didn't feel they took advantage.

We recently spent a week at the Hilton Terminal 4 and on the second last night decided to splurge and give the Zen a try. We noted that the restaurant seemed quite busy each evening, the selection looked good and the prices (excluding the wine) weren't too outrageous, especially for an airport hotel, which has a captive audience.

On our chosen evening, I did a quick scan of Tripadvisor to see what others' had to say and noticed that the restaurant would to takeaway. So we went downstairs, verified that this was possible, placed our order and quickly went to the Marks & Spencer in T3 to get a bottle of wine. When we showed up to collect our order, it was just coming out of the kitchen.

The two dishes that we ordered (can't remember the exact name but one was a chilli beef and the other a spicy chicken) were delicious. The meat was tender and flavourful and one order of rice was more than enough for two people. I would definitely recommend this restaurant and if you do the cheaper option (i.e. takeaway) the prices are very reasonable.

I couldn't tell, but I am guessing that this is likely a favourite of those living locally and business isn't only relying on hotel guests.

I avoided eating here on prior stays at the Hilton figuring the cost could not be justified. I was wrong. Despite a captive clientele, the service and food was outstanding.