I also am currently a student with ATP. I earned my PPL with a mom & pop shop in 2010 and started the airline career program with ATP Richmond in Feb 2013.I have found it to be an EXCELLENT experience. The the instructors in RIC go well above and beyond whatthey are required by the company to do (i.e. giving extensive ground/classroom instruction). That being said, when I was in my cross-country time building phase, and again in CFI school, I saw instructors in the company who simply don't care and don't give much ground, if any. It is all about who you get and how much effort you are willing to put in. If you are seriously considering ATP, I would highly recommend the RIC location, as you will not find better instructors anywhere else. They go well above teaching you to "pass the checkride." I have been fully, if not overly prepared for all my checkrides and have passed all (including CFI initial) with no failures.... we have some tough examiners in Richmond too.
There are a huge number of different ways to get your ratings and hours. You have to figure out what is financially and logistically right for you. I did not attend a 141 University flight program (I have a non-aviation degree), but I can tell you that the airlines do not care where or how you got your ratings. ATP sends scores of its instructors to the airlines and ATP also has airline agreements.... Republic is even interviewing ATP studends after they have secured their commercial ratings and giving them conditional job offers so long as they instruct WITH ATP. I say this with no bias, as I will not be working for the company. I have a gov't job which I need to keep until I go airlines, so I will be instructing at the mom & pop shop near my house in northern va while working fot the gov't.
There is nothing wrong with a University program either.... I have heard great things about some of them. I do know that it can be extremely expensive though. Again, its what is best for you. If you already have a degree...obviosuly a university program would be a huge waste. And as for the "airlines prefer aviation degrees..." that statement is completely false. Talk to any airline pilot... They will all tell you NOT to get an aviation degree. In the even of a furlogh, you want another field to fall back on. I know many pilots, corporate and airline. Very few have aviation degrees. But, on ther other side of that argument, there is nothing wrong with an aviation degree if that is what you want. Bottom line is that you need a 4 year degree...but not in a specific field.
Personally, I don't know much about Aviator. I did look at them when I was researching schools, but at the time they didn't offer financing and I would not have been able to keep my gov't job in Virginia... so ATP was the best fit for me.
I encourage you to take a tour of the ATP location you would be interested in (and the aviator location). Meet the instructors. If you don't like them or think they will do nothing but the minimum, look at another location. Again.... I highly recommend RIC. Jake, Derek and Diego are all really good instructors who go out of their way to ivest in your success.
If you have any specific questions, don't hesitate to ask. Also, take a look at my running experience thread about the ATP program.