I stayed in Alux Cancun with a friend for four nights in February 2008. It was nothing special, but good value for money.
Both the room and the bathroom were clean and nice. The beds were comfortable and the room was quiet. The only minus was that we only had a tiny window, so the room was dark. But if you only need a place to sleep, this is it!
Some of the staff speaks some English, but not all of them.

This review is for the Hotel Alux in Playa del Carmen, not Cancun.

Alux is an excellent budget choice. We were there the week between Christmas and New Years for 7 nights. All the other hotels in town had raised their rates substantially. Alux was $55 per night. Great location, very friendly staff (no English spoken), very clean, comfy bed, cable TV, charming decor including brightly painted walls and mexican tile throughout the room. The overall atmosphere was very fresh and clean. There are no frills, but we were impressed with the value and comfort.

In downtown Cancun, there are many places to stay near the bus station. Hotel Alux is my favorite. Medium-low price ($30. single), clean, friendly service. Somewhat old, but new mattresses and magnetic locks within the last year. TV and AC. The main drawback is the stairs, for this hotel goes up, not out. Location, convenience, price, and service make it my favorite in downtown Cancun.

I was looking for somewhere to stay for my last night in Mexico before a very early flight out of Cancun the following morning. I contacted several small hotels in downtown Cancun, the Alux was the only one to respond, and I made my reservation. Their correspondence was always quick and businesslike.

I was quite happy with the hotel - it is far from being the Four Seasons, but for the price it is very acceptable - rooms are nothing very exciting, but mine was spotlessly clean, with amazingly crisp white sheets on the bed, tiled floors, and clean if tired looking bathroom. For me, the location was great, right in the middle of everything in downtown Cancun. If you want to be right on the beach of course, this is not your place. To mix with the locals in the downtown area however, it is perfect. I would stay here again.

I am rating the hotel as 'above average' based on the cleanliness and the value for money it offers.