As for the polyquat, it's your choice - the old forum had some threads that advocated both ways - I'll try to sum up the oppinions from (failing?) memory.
* Con - it's a waste of $ if you keep your cl in check and sufficient
- why add an extra chem to the pool if you don't need it?
- never used it, never needed to
- tried it once but it foamed up the pool (that was a cheep algicide, which are notorious for foaming)

* Pro - It's an insurance policy against algae (sometimes you forget to add or check the cl )
- the amount you add is small (for a maint. dose) so a quart or two lasts the whole season.
- ' I just feel better knowing that it's there'
- 'I use it but I only buy it when it's on sale at "X" (store)'

In short, it's a matter of choice - if you're sure that you can and will keep up with the pool using bleach, you don't need to use it - if you're unsure, add a few oz. every other week