I love them!
I had my Algebra kids color and cut their own set one day. It took a full day (90 minutes!) in the classroom, and then some more at home for some kids. (1)
But, even with the loss of that teaching time, I think the benefits of Algebra Tiles are so worth it!
I like having something concrete to refer to when dealing with the abstracted-ness of algebra. I like having something to point to when handing out rules (2) like "5h and -4 can't be added" and "5h and -4 can be multiplied, and the answer has an h in it" and "a number with parentheses next to it means multiply that number by everything inside the parentheses"
Most kids don't need but one or two examples with the tiles, and then they're good to go with the "symbol version" as we call it. But, I like having them out, and having the kids know how to use them, so a) I can refer back to them when a kid is struggling and b) kids have a way of checking the correctness of their answers without me.
I spent a long time with these algebra kids doing some basic stuff, like integer operations. When we started working with variables, I was a little worried. But, the truth is, they've done extremely well with it, and we're moving along faster than I anticipated. I love it.
(1) Mostly, I think kids were milking it, and taking advantage of the non-math time!
(2) I don't actually "hand out" these rules! We spend time making sense of them, Algebra Tiles or not.