If it works for you and you're happy then that's all that matters in the long run.
I personally wouldn't have it on my computer..it's discussed way toooo much on the internet and download sites such as cnet by reviewers to what it places on your computer as far as tracking and more.
I use the same software you do...(minus the eBay toolbar) Spybot, Adaware, Spyware Blaster and even the Spybot forums discuss the eBay toolbar and what all is running with the add-on.
I also use FF browser the majority of time...and I haven't checked (there's no need to) there is no eBay toolbar for FF for security reasons.
Here's just a few links that discuss this issue.
On this link go down to Hummger-ga response:
http://answers.google.com/answers/threadview?id=328675
Everyone has to make their own mind up about this software and what they want on their own computer.
http://www.safer-networking.org/en/threats/259.html
This is an older link but it's still good and explains what is running under the eBay toolbar.
http://www.auctionorbit.com/misc/toolbarspyware.htm
And this is a GREAT page thatlets you know what's running in the background when you're viewing eBay. If you ever wonder why it's running slow....click here:
http://cgi3.ebay.com/ws/eBayISAPI.dll?ViewUserPage&userid=rockboss2000
Look at all the things running in the background. If you ever wonder why eBay runs so slow...Mediaplex etc.
Links which state eBay spyware via the toolbar.
http://www.intranetjournal.com/spyware/identify.html
http://www.cites.uiuc.edu/security/antispyware/info.html
My best,
Donna