I use Agent Office and have for 2.5 years. 

I've used Goldmine in the past (and ACT prior to that), but I wanted a RE specific database when I got back into RE sales 2+ years ago.  I now have about 3,000 records on the system and it's been a great investment.  And, the ROI increases dramatically over time.   

There are lots of advanced features like you would expect - Mail Merge, email forms, management of contacts by categories, notes, automated reminders (for house closing anniversaries, birthdays, etc), multiple addresses, info for all family members, etc., etc.  The key is that I'll seldom hit a block wall where there is something I really want to do that the system won't allow me to do it.  

All databases take work to keep them up to date, and the idea of using a Rolodex to look up addresses and phone numbers is certainly valid, but databases need to serve so many more useful purposes.  

e.g. I run a REIA in Des Moines, started in fall of '06.  In order to keep people informed about upcoming meetings, I use three primary methods - I update the website, I send form emails, and I send snail mail to those folks from whom I have not captured an email address. Believe me, one of my first goals is to get an email address to enhance our ability to communicate!  

With the high cost of postage, I am working harder all of the time to make sure I have people's email addresses on file.  Once I compose the notice, it takes me all of about 2 minutes to select the "Email on File" category, and send a customized email message.   

Is it effective?  Kind of.  Is it efficient?   Absolutely, unequivocably the fastest option available!   I'm only sending about 50 messages now, but the system can easily grow to my targeted 400 and take little more time.  

When I send out my newsletter, to about 1,500 folks, my database allows me to print all of the labels in minutes, sorted by zip so I can take advantage of BRM rates -- with a Rolodex, this would be impossible. 

I'm sure others have worked out a system which works for them with these generic database systems, but if you want the very best, IMO, the choice is Agent Office.  There is great training available from Gary David Hall.   And, I have a second hard disk in my system that I use for backups, in addition to writing the file to CD now and then.  That's a pretty good insurance policy against data loss.