Hello and welcome A. I have been an integrator for FI's for 30 years. If you have no integration needs (tellers or ATM) then there are several that will work well for you. We have installed over 2500 March systems. Verint is good, and so is 3VR. Just my opinion not knowing your details; 20MP is overkill for sure. You can take that money and spread it all over your lobby and workrooms and still get excellent video. As John said, 5MP sounds high on the outside, but if you have a large parking lot, it might not be.
You did not mention if the branch staff will have any access to the software, but all things being equal, they will not. Statistics also recommend installing a Lobby Monitor. Let potential robbers know you are recording. You don't have to show them all the cameras.
Make sure you use WDR cameras. Most FI's have a lot of glass, and they are open later (in the winter months), ATM machines, night deposits, and the lighting will be every type you can imagine.
I would make sure you choose a VMS FULLY integrates a broad range of cameras to interface with. This system will last you years and you need to be able to integrate new features down the road. If they do a good job keeping up with the software camera manufacturers develop, that will help you two, three years from now.
I do like Exaq as well, but the whole Tyco thing bothers me as an integrator. Will they lock me out of certain features in favor or ADT? I have seen it before.
Your VMS does not "have" to supply the cameras, but in the IP world, it does help. They will always fully support their own product.
As for cameras, Samsung is good, Panasonic has always had a good product, I do like Hikvision despite their recent bad press and all of them can be bought for a reasonable cost.
As for the VMS, don't concentrate on price as much as use. You will use it for days, then not turn it on for days. It needs to be easy to use. Can you use it after not having used it for days or weeks at a time? Does it help YOU? Keep it simple. Good solid VMS, good solid cameras, good strong sound switches. FI's don't have the time to manage IT. They are in the money business. I would also choose a recording device as opposed to loading software on a server. A purpose built box will generally be simplier and easier to manage and last a little longer (IMO). I would recommend that you be able to offload video with a watermark, AND that plays in a univeral media player. The police won't want to take the time and effort to download a player unless it goes to court.
It sounds as though you put your decision into the hands of someone else. There is nothing wrong with that as long as they have a good reputation. Make sure they are certified. If they are installing on your network, make sure they have network experienced installers. It will be important at some point. Decide from the gut. Who are you comfortable with? They should have your interest at heart. Don't worry as much about the equipment as the people involved. Ask to meet the installers and service techs. Do they install their own equipment or sub it out? We are all in the people business.
One last thing. I know a ton of people think 30 frames/second is cool and it is. Just my opinion, it is overkill, particularly in an FI. For years we made 1 frame/second work well. Cut down on the frame rate; you can cut your storage cost and bandwidth and still have plenty of video evidence. 5-10 frames per second is plenty. Keep it simple. But yes, it is way different than analog and yes there is a ton to know. It is far more complex. Good luck to you!!