Citizenship comes with only drawbacks these days.
You can be a temporary (think H1s, student visas, etc) resident, a provisional permanent resident (essentially it's what lets you be a resident for the extended period it takes to approve a green card in which your original work permit might expire), or a permanent resident (i.e. a green card), and in all those cases you pay at minimum the same taxes as citizens.
On the other hand, if you just walk across the border, you qualify for all of the benefits, and even now get to vote just like citizens, but there are no obligations at all. You even qualify for free housing, free healthcare, free internet and cellphone service, and free food, just for showing up without papers.
Non-citizens pay at least the same taxes as citizens, I recall there being some write offs that were only applicable to citizens so it's possible that non-citizens pay more in some cases.
Obviously non-citizens also pay the same sales taxes as citizens.
The only difference is you don't get a say in how your tax dollars are used. So much for "no taxation without representation".
Oh, and have to budget time for "random" delays at airports.