Professional staff. They were always helpful and attentive.
I got a room on th executive floor, it was super clean and spacious.
This is not a new trendy place, but it has lots of charm and it is very well located in the heart of the city centre.

Had the misfortune to be back in this dump again recently. Expect a comment from the manager talking about the refurbishment master plan that is going to be Enacted soon. Sigh! yea sure, we've been hearing that lie for ten years now.
OK the good stuff:
They do security fairly well and that is wholly necessary.
The staff are nice and try to be helpful
Errm, thats about it.
On the downside:
The rooms are apalling , dirty, musty, smelly . poorly furnished.
Food in the restaurants is vile... hint: last nights unsold fish curry is not an appealing brekfast.
Internet is dreadful and they rob you by charging $20 a day for it! Go out and buy a Safaricom sim card and get 1GB of Data for $5 and use any smartphone as a wifi hotspot 4G network is much better than hotel broadband anyway.
Because of its location and the name it carries this kip has a very high occupancy, and the rates they charge are ridiculously high. Someone is creaming an absolute fortune off this cesspit. Conrad Hilton would be spinning in his grave if he saw this dump using his name, never mind the very unfair impression it gives of Nairobi and Kenya as a destination.

I stayed at the Hilton for 4 nights. The reception area is very grand and impressive as is the dining area, giving a great first impression. Staff were friendly and attentive.
The security was tight and my bag was searched on each occasion I entered the hotel, which was reassuring.
The bedroom didn't meet my expectation, although clean, tidy and a reasonable size, it was not as modern as the public areas, I would describe it as dated, and showed some wear and tear.
The swimming area was really well presented and quite considering the busy city location, towels were provided. There is a snack bar located next to the pool area and a changing area. The gym is well equip and air conditioned it also has a changing area, which was extreamly clean with showers, a sauna and steem room.
The bar, snack bar and resturant are very expensive when comparing the prices to other eating establishments as was the hotel. However the food was nice with a good menu, something for all including children. The staff were very polite and attentive, maybe a little to much at times. Breakfast is excellent a great varity of hot and cold items, Buffett style.
Over all, a little expensive but would stay again if I was visiting Kenya.

I was little bit surprised since my expectations were maybe too high. Probably if you lower your expectations from ''real'' Hilton standards, you may be just satisfied. Location is also not the best one from security point of view and if you do not have local friend or tour guide accompanying you, do not even try going out of the hotel. Service is not bad, sometime slow but this is compensated by friendliness of the staff. Would I come back again? This is the question....