If you're thinking about getting it, do it.
Positives: 1. Heineken tastes so much better out of the keg (no skunky smell like you sometimes get out of the bottle). And, the beer stays carbonated for weeks. 2. Convenience - couldn't be easier. Replacing the keg takes all of 90 seconds and having a great beer on tap all the time is brilliant. 3. Entertaining - great when friends come over to visit or when the guys come over to play cards. 4. Appearance - the stainless and black is hip enough that your wife will probably allow you to put it on the kitchen counter. If you have a game room or den, even better. Takes up same space as a toaster or coffee maker. 5. Cost - $20 for a replacement keg and $1 for the new tube each time adds up to a pretty good price per pint.
Negatives: 1. Currently only Heineken kegs fit the BeerTender. 2. The 5L kegs are currently difficult to find in my market - but, the distributors have told me that it should be resolved by Feb 09. 3. You should really keep a 2nd keg always on hand so that you don't run out. If you have a 2nd frig, then no problem. The thing is, if you have to run to the liquor store for a replacement, then it's a pain and often, the one you bring home from the liquor store needs a little time to cool down before serving. Having a spare, on-hand and pre-chilled, is beautiful.