I just got back from there and completed my Irish ME/IR flight exam last week successfully. At last! I also did my CPL there last October.
Overall, I would recommend them. They unquestionably get people through training and most everyone passes the exams. (No one failed while I was there but of course people do fail from time to time). They had an examiner over from England and he was planning on doing about 10 flight exams while he was there - so they do get results.
The standard of instruction is good. In particular, Roy for the CPL is universally liked and extremely knowledgeable. The chief flight instructor has a lot of flying experience although he will put you through the wringer on the 170A.
Their facility is pretty nice - and the airplanes are in fairly good shape. Stuart is right on the beach so after a hard day's flying, you can wiggle your toes in the sand. The hotel is a bit of a dump but the price is right. It's walking distance from the school (about 15 minutes). They have some bikes you might be able to borrow - though your enjoyment of Stewart will be hugely improved if you can afford a car while you are there. If you are going to be staying for longer, I believe you can get an apartment.
There are a few things to watch out for -. .there are some additional fees such as examiner fees, 170A fees etc that are not included in package prices. Also, package prices are for a set amount of flight time - if you need more time it will cost more money, but that is the same pretty much everywhere.
Also - it seems like they could be a little more organized with how they handle students on a daily basis. Although everyone gets what they need in the end, there is a little more stress in scheduling instructors, airplanes and flight exams than there needs to be, in my opinion. They were in the process of buying another twin and complex single while I was there, which should ease airplane scheduling difficulties.
Overall, you are likely to get the result you are looking for in the time you have and for approximately the price you expect. This time of year is particularly good to go there from a weather standpoint.
If you have any specific questions, please feel free to email me.