Leopard on Non-Intel Macs

My BIL has hired an "expert" (according to him) to set up a new MacBookPro.
While doing so, he also set up Time Capsule for wireless backup.

When he asked the guy about putting Leopard in his iMac G5, so that
machine
could also utilize Time Capsule the guy replied that Leopard was developed
to make use of the Intel-based processors, specifically multi-core
computers
and that, although they can run Leopard, G4 and G5 Macs should stick to
10.4
Tiger OS. This expert indicated that some functions of non-Intel macs
would
be impaired running Leopard (10.5.x).

Further, (farther?) to take advantage of Time Capsule, the Tiger OS driven
G5 could use a new and much better software for that task, called QRecall.
Checking into it, it looks like it is in ßeta stage of development.

Yesterday, in the Apple store, I was talking to a 'near' Genius, who
confirmed that QRecall was indeed a very good backup utility that will do
incremental backups and if one item changes in a folder, the whole folder
would not be re-written. He also indicated that he felt Leopard was not
the
preferred OS for non-Intel macs, which should stick with Tiger.

Anyone care to jump in about these two items? I have a dual-core G5 tower
that I have been considering moving over to 10.5 for consistency (my other
machines are now on Tiger). However, I may not do so if it will muck up
the
computer. TIA for any (constructive) feedback!