OK, the chance to look up and down the Danube River and across the Slovak National Uprising Bridge to old Bratislava from 85m/275 high is irresistible. Yes, there is a decent restaurant at the top if you want to be formal, or you can just choose something light served at one of small tables lined up along the windows. It's a big place. We had a lovely late-afternoon snack of wine and pastry, priced a bit on the high side, which is perfectly understandable, given the unique location and character.
But so what? It's a million dollar view. Like other such stuctures once colorfully called "space needles," this one invites you there to gawk, so enjoy it. The food and libations are a pleasant addition. We enjoyed ours, taking our time so we could see and photograph all the views. The staff were very pleasant; no one rushed us, and in truth all the employees seemed to be as happy as were, up there taking in the sights on a splendid day of blue sky and long views.
It's a short easy walk from old Bratislava over the bridge named above. If you want to add a bit of exercise ahead of dining, you can always choose another bridge crossing and hike on the opposite side of the river to get to the UFO which is, after all, built on the side of the National Rising Bridge that is closer to the far bank.
We chose to cross on the Lanfranconi bridge, as that took us through an interesting part of the city, with good examples of art nouveau architecture that we wanted to see.
It's quite a trek, and some of the pathway is a bit crumbly and at times hard to navigate, given the number of public recreational areas and boat/ship moorings along the way, but it gives an entirely different view, whets the appetite, and IMO is worth the time and effort -- assuming you're fit and curious enough to want to go on your own route rather than just following everyone else going there by the shortest, easiest way.