Congrats. There is a lot good companies out there, and you have received a lot of good answers already. I started with Exit and remain there. Each office is independently owned, and my broker offers very inexpensive CE classes for agents for any company, Exit has online training as well to help you get started in the business when you cant make it to the office.
I would suggest you interview with a least three different brokerages one big, medium and small & see what fits your needs.
I would start by looking at one with Real Estate Lic Schools. They usually have great new agent training and have a vested interest in grooming new agents.
I started with Century 21 when I got my lic. I found the traing to be very helpful and the senior agents had no problem offering their advice and wisdom.
Much Success to You!
Kawain Payne, Realtor
Training is important and always most important when you're new. Nowadays I think that there are so many opportunities for training outside of the office setting that it might be a bit less critical a factor. You also want to think about size, culture, market share, agents' success, reputation in the market, quality of administrative staff, managerial approach, etc.
Sometimes you can get end up with a large slice of a small pie in a small boutique office. Other times a large office may be a market leader and have many successful agents which brings an energy to the office - and lots of listings which gives you potential open house opportunities, floor calls, etc.
I wouldn't be too focused on commission split except to feel confident that what the office is offering doesn't fall outside local norms. You also want to find out if the office has a non-compete agreement and think long and hard before joining an office that makes you sign one.