Some things to consider:
Is Gandalf your first LOTR PF or do you have a lot of them? It would certainly be easier for you to collect a line that's just starting than it would be to try and hunt down all of the PFs you missed, and Lurtz is going to cost you.
Also, the maquette line is going to have more characters made. In four years we've seen 11 PFs (or 12 if you count Mordor Orc) revealed. We've already seen seen 5 sculpts revealed for the maquette line in less than a year. So would you rather have a smaller collection of larger statues or a larger collection of smaller statues?