Specifically, for the main support beam found in a basement.
Talk to the supplier of both the products on what is involved in installation, weight bearing over the span you are trying to go without supports,the size of beam, will it affect the height of the room below or will the floor have to go up and the cost how much are you prepared to spend, you will then get your answer
Glulam. Cheaper to buy, cheaper to install. Takes up less space than an I-beam.
Depends on what you mean by better. Steel is more difficult to work with and now more expensive. Glulam can do everything that you need in a home. You would be able to span further with steel, but that is not usually an issue in a home. Personally I would use glulam.
Steel is better. You can use a smaller size compared to wood, it will handle more weight and will not deflect like a lam beam can and will. I've worked in a lot of older houses and the ones with steel beams always had far less differential settling than those with wood beams.
