I have to disagree with your claiming that the 3705 is not reliable.
I've talked to people who spend their lives upgrading and repairing
3705s who will testify to the reliability of the 3705.  We have two and
they are some of the most reliable pieces of equipment in the machine
room.
 
Of course if you overheat the power supply it is going to give you
trouble.  Electronic components don't appreciate being overheated.
 
As to the 3725, why buy one new when you can get an equivalent 3705 for
1/3 the price from a used equipment broker (at least here in the
states).
 
Jeff