We play every Thursday night at guardian games in Portland. Come out and try a game or two, we all have armies to spare and would love to teach a new player!
To answer some of your questions (now that I'm in front of a keyboard)
1. Diversity in lists - How lists are built in this game you have an HQ unit and Combat platoons as mandatory platoons. Then you get tons of support units to support that core formation. There are a variety of lists (especially for the US and GER), but if you have one set of infantry, that set will be able to work for both mid war and late war (early war formations may be a little bit different but usually you can make do). Each time period focuses on something completely different and are very diverse. Early war and Late war you will find the most options as those have recently gotten face lifts from battlefront. In early war you have something like 9 nations to choose from, 3 theaters of war, and a TON of toys. Late war you will find the mighty beasts of the war King Tigers, Panthers, IS-2's, Pershings, Comets, etc.
2. Ahistorical Amounts of Limited Resources - That is something that you may not enjoy about this game, you will see an ahistoric amount of King Tigers and other super heavies running around on the board, BUT the points system heavily penalizes them and you certainly are never forced to play with the limited number of toys. If you want to run nothing but Shermans, T-34s, and Pz IV's then you can do so and be competitive against the big toys. I.e. the King Tiger is NOT the King of the battlefield.
3. Where to start my collection - I would start with the Open Fire box if you are planning on playing US or Germans. I don't play Russians so I don't know how to guide your first purchases. For British I would start with a company of Infantry, 2 blisters of 6-pdr guns, Mortars, and 1-2 boxes of Shermans. These are all late war armies, because that is what is played the most so you will have the easiest time finding a Late War game.
4. Limited number of Competitive lists - Certainly not, there are some lists that are more competitive than others but each nation has a plethora of competitive lists especially in Late War and Early War (Mid war only has 2 source books so the number of lists is smaller).