It's worth it if you'd normally make and waste most of a pot of coffee each day. It's worth it if you're the only coffee drinker in the house. It's worth it if you and your SO like different types of hot beverages. It's also a good idea for an office, because then no one feels forced into just drinking coffee - you can have all different types of coffees, teas, you can do hot chocolate, etc., etc.
I have one and love it.
The permanent filter is great and cost saving, but you do need to be careful about the grind on your coffee if you go this route (it needs to be coarse, not fine).
A lot of the grocery chains now carry their own brand of "K-cup" knock offs, so there are cheaper versions of them now. Amazon has them for a reasonable price and if you sign up for their delivery service, you get a discount. And, I'm sorry, but they are NOT a dollar each. That's ridiculous.
Regarding the "strength" of the coffee, there are LOTS of different ones out there, and there are some very strong ones out there, so you can experiment until you find one that you like.
I say, go for it!! If taken care of properly the machines last a long time. I have had mine since they first came out and it's still going strong. Just make sure you're not using regular tap water.