Backup pools? Good idea? Bad idea?

[mokahless]

Just wondering what everyone's opinion is on CGminer's backup pools without --failover-only?
So in other words, does anyone have any idea if leaking work to other pools would increase or decrease overall efficiency?
I used to have just BTCGuild set up but not I have backups at Deepbit and P2Pool. Haven't been running the backups very long but I seem to be getting ~0.005BTC every time a block is found (3 times today in the last 24-hours). I haven't had this setup long enough to determine if BTCGuild is affected to a major degree or not, especially with the small, non-configurable estimation window. Deepbit averages ~20MH/s in a 60 minute window.
I'm running windows 1x 840MHz unlocked 6950, 1x 725MHz 6450, 1x stock 6770m and linux 1x 1.02GHz 5830 all with CGminer.
Thoughts?

[eleuthria]

Having backups is always a good idea.  The only "downside" to them is a backup pool without --failover-only [possibly with it too, ckolvias can answer] is going to be using a longpoll connection on your backup pool, which is a slight drain on resources for the backup pool.  Not huge, but given enough miners that are only connected by backup, it can lead to a minor delay (few miliseconds, maybe a few hundred miliseconds if many miners use it as a backup) for other miners on that pool before the work generation of the poold is able to answer all of the longpolls.  But the benefit for miners far outweighs the almost invisible load added to their backup pools.

[-ck]

cgminer doesn't spawn a longpoll for backup pools any more since 2.4.3 except in "load balance" mode. So it's very much a good idea to set up a backup pool as no pool is infallible.