Overloading relational operators separately; thoughts?

[Sai via Digitalmars-d]

>    a.isLessThan(b)


I understand the concern of possible mess due to unrestricted use 
of operator overloading (like C++). Java has clearly driven the 
point home by banning the operator overloading altogether.

Genuine question: In the post Java languages, how many languages 
allowed unrestricted operator overloading and did that cause any 
similar mess?

Thanks in advance for any answers.