It's all about expectations with the iPad. It's not going to be a pure laptop replacement if you do any "serious" work (don't even think about web dev for example, although it would be awesome if Panic released Coda for the iPad), but for about 80% of what I do (especially when traveling) it's absolutely perfect. Combine that with home use, coffee shops, and instant child entertainment and you have a device worthy of your $500.
If it doesn't fit into your life, don't get it! I still don't understand the point of the reviews where they try to do EVERYTHING possible on the iPad. It's clearly not meant for that, stop treating it like it is.