This is a subject that unfortunately comes up far too frequently with our Aveos. You will find multiple opinions on this, and one important factor is the repair estimate. For those of us who DIY, it's usually a no-brainer to try the valve replacement or just pick up a reman head. Not a big $ risk going that route.
Outside of DIY, the shop price for this repair has recently been posted at 1.5 - 2K, which includes the required timing belt job redone again. At that price, I believe the better choice would be a rebuilt engine that includes a 1 year warranty. I feel that taking care of the head (one way or the other) is a crapshoot. The valves get bent by smashing into the pistons. And because of that I wouldn't have any comfort level putting that kind of $$ into an engine which took that kind of a pounding - bearings , rods, etc.
Now having said that, I also need to add that I'm in the minority, because most guys have no problem throwing on a new head. You said that the shop will "work" with you, so maybe with a reduced price it may be reasonable to go with the head only. Good luck with it, regardless of which way you go!