There is a lot to consider when replacing the brakes on a vehicle. The first thing I would get from the mechanic is the brand and grade of pads and rotors that he is going to replace these with. I would also request the thickness of the rotors, and compare them with the manufacturer's minimum thickness and see if they can be "turned" (a process of essentially "shaving" the metal down until it is a smooth service again) instead of replacing them, provided the rotors are enough above the minimum thickness to accommodate the process. Another thing to consider is friction material. Most manufacturers will recommend a certain friction material and it is, IMHO, always a good idea to stick with their recommendations. In my experience, most newer vehicle manufacturers recommend a ceramic pad, as opposed to the cheaper "semi-metallic" pads. The other thing that you will have to keep in mind is the labor rate of the mechanic, which, at least here in the States, tends to be much higher than the cost of the parts. Another thing to consider is the warranty attached to the items. Being that pads and rotors are a "wear" part, there are a lot of places that will not warranty on wear. However there are a few brands/stores/mechanics that will warranty the part when it is worn out, saving you from paying the money again. Just as a reference/comparison, I recently replaced the front pads and rotors on my Pontiac Grand Prix myself, and "Top of the line" Wagner Thermoquiet Pads (ceramic) and Bosch rotors cost me right at $200, just in parts. However, these were purchased at a local parts house and not online where prices are a lot cheaper.
When it comes to wipers, there are many "schools of thought" that I have come across. A lot of people think, that since they are going to replace them roughly once a year, in the location I live this is about normal, that cheaper is better. Personally, I prefer a good brand that is going to hold up better, if taken care of properly, and require less maintenance.
From my personal experience, there are some automotive shops that will not perform the work with customer supplied parts, or if they do, they will not have any type of warranty or guarantee with them. I would also find out the shops policy on this as well.