Thats rly up to you and what you use your phone for. I played with a little bit and its exactly what I need/want in a phone I think. If you use it for business its probably not a good one for you. But if you want a phone with good multimedia functions then its probably a great buy.
Important features of my blackberry that I like:
1) email - I have 2 hotmail and gmail accounts and my 8130 can be programmed to receive all 4 accounts.
2) Phone as a modem feature - I use this alot when I'm out of town
Does the instinct support these 2 features??
Your best bet is to call Sprint for PAM... I have heard mixed reviews. Some say its $15 extra and others say its not possible so I would call them to ask.
Currently Phone as a Modem is not an option on the "Simply Everything Plans" that the Instinct requires, so if that is an important feature to you, you would probably be better served with a Blackberry or one of the other Windows Mobile phones.