Which battery is better?

I'd posted this by mistake to only regional forum.

I was planning for a standby battery for my Canon EOS 30D. I saw Canon's BP-511A Lithium-Ion Battery (7.4v 1390mAh) priced at $49.95 at B&H and also Impact's BP-511A Lithium-Ion Battery (7.4v 1500mAh) priced about $15 less.
Has anyone used both & found differences in quality? Is the $15 price compromise not worth it?

Let me know
Gautham

For only $15 extra I'd go with the Canon.

I use Nikon, and the price difference was roughly half ($59 vs.$99), I bought a Promaster back up battery and have been very satisfied to date, but I have heard from others that some brands of the non-manufacturer batteries don't hold up well in cold weather. I have no personal experience with this however as I live in Florida.

Check out www.sterlingtek.com which sells a BP-511 for around $12. I have one Canon battery for my 20D (that came with the camera), and two of these Sterlingtek's. I had all for about a year and a half, and swap through them. I cannot tell any reduction in quality in the Sterlingtek batteries compared to the Canon battery.

http://www.sterlingtek.com/ln03-canon-bp-511-dlc511.html

Thanx guys. I've ordered Sterlingtek battery.

I have three sets of 2 sterling tek BP-511 replacement batteries, which I've been using with my 20D and battery grip for going on two years. Long life, no problems whatsoever. And cheeeeeeeeaaaaaaapppp!