First of all, keep in mind that Haiti is unfortunately one of the most poor countries in the world (158th in HDI 2011), and the country lack some infra-structure and supply. So, that said, the hotels here will hardly achieve the same standards as hotels in the developed world or developing nations like Brazil. Before complaining about anything of Haiti, you must know why things are as they are.
ok. Now, about the hotel. It is located right in the city center, very close to the Palais Nationale. Altough located in a noyse part of town, the hotel is very very quiet and the outdoor area makes you feel you are not in Port-au-Prince but somewhere far from the capital.
There is a nice pool and bar and lots of beautiful plants and trees around. You can seat in the bench next to the pool, drink a Prestige beer (very good one) while reading a book or using a laptop (there is good free wi-fi internet). Again, it is quiet.
The staff is very nicem both at the reception, bar and restaurant, security guys and cleaning ladies. In fact, all haitians I met are very nice people.
I stayed in two rooms. The first one was just temporary because I arrived at the hotel earlier than the check in time, so my room was note ready yet. I asked for them to arrange me a room so I could take a shower and use the bathroom (well, after hours of travel from Brazil, I needed it). That room was not good, but it had tv, hot shower and ar conditioner (luxuries here in Haiti as most of people don't have even a house). My second and permanent room was very good, large, two very confortable and large beds, tv with lots of channels (altough I didn't use it), hot shower, strong air conditioner, frigobar, balcon, etc etc.
There are some little problems in the room, but I didn't mind at all (knowing the situation of the country) like small cracks in a wall and the bathroom had some cracks too and an old bathtube.
In my opinion, everyone in the hotel did a good job.
Even comparing with Petion-Ville hotels, this is surely a very good option. My boss was with me and he had already stayed at Montana in Petion-Ville. He told me that altough Montana is better, Le Plaza don't lag much behind.
The only problem of this hotel in my opinion is the breakfast, which is not included (costs US$ 11) and there are not many options of food. Well, for people who like to eat meat, sausages, eggs and other heavy stuffs, there are, but for a brazilian breakfast (bread, fruits and cereals) there are not many options, just the basic.
Enjoy Haiti, it is an incredible country with an awesome people.

Room and Service staff is nice, only drink water 2 bottle on you arrivel, over you need to buy in bar, its not give you 2 bottle a day, so you stay longer no good, becasue you need pay more for drink water, internet repair say one day, but I wait 2 day the room internet also no connection, only in publice area.

Stepping off the noisy and dirty streets in the Champs Mars area of Port-au-Prince, it’s a quiet relief to enter Le Plaza (which years ago was a Holiday Inn). Reception area and hallways are nothing to impress, but when you open the door and enter your room you know you’ve come to a quality place. The room was small but very comfortable and clean, nice bathroom, very comfortable beds, good air conditioning, so I was happy.

The courtyard is a very pleasant place, whether sitting under the large gazebo roof to eat, in a lounge around the pool (which is old, some paint-chipped, but clean and pleasant swimming), or in a grouping of outdoor seating under coconut palms.

The food is good but not great, and for Haiti it’s really high priced, but that has a lot to do with what’s happened to prices all over Haiti since the January 2010 earthquake.

I am a "regular" at this hotel. The staffs are wonderful, my room was very cleaned and comfortable. I had to extend my stay and had no problem changing my reservation. Security was no issue for me. The food is ok but a little pricey. Will stay again, and again.