If you have asked for a pair they will offer you up the choice of all of the pairs that are accessible. Before anyone on the registry is offered their seats current season ticket holders are able to go and choose from what is available. At the end of the day, all the seats not taken by current season ticket holders are then made available to #1 on the registry, and if they decline, to #2 etc.
You get a few small tokens per seat you have. Oilerbucks, discount at the oilers store and partner restaurants etc. You also usually get a couple of free tickets to the Oil Kings home opener and "VIP" invites to other events. Also, you will see a higher chance of winning things on those "Fan Appreciation Nights".
You will also have an account manager assigned to your season seat account and they can help you with requests related to the team. I have used this to get jersey's autographed for my wife and things like that.
All current season ticket holders are being assigned seats in the new arena that are supposed to closely match what we currently have. Sometime in July they are supposedly opening a office somewhere which you can sit and see a virtual experience of what you seats will be like in the new building. You can then upgrade or move around if you wish.
If you have any other questions let me know..