• View whois information
• Add your domain name to watch list
• Receive instant notitications about payments pending
• Store password for control panels, userful links for every domain
• Make short notes about every domain
• View whois information for website you currently visit in Internet Explorer
• Query DNS records

Yes, registar will send you notification emails about pending payments.
But can you bet you will receive those emails?
Do you have SPAM filters configured correctly?

SoftCab Whois will will stay out of your way in system tray area, and notify you about all payments.