Just wondering. '.' just seems more intuitive.

I don't think 'intuitive' is quite the right word, although more familiar perhaps. The basic answer is PHP uses -> because both the -> and . operators are from Perl. I'm not sure why Perl chose those symbols for those operations.

. = concatenation. It's been that way and I think it would break backward compatibility to use it for OOP.

oh yeah! i totally forgot about that. Those languages that uses . for objects: what do they usually use to concatenate? +?

I use ->
Don't know why.. Probably the tutorials I read when learning PHP, or the fact I think its easier to read.