The Good:
Thematic new weapon choice for casters.
Includes lots of support including traits, feats, enhancements, unique weapons and archetypes.
Good alternate weapon for spellcasters who want to extend their adventuring day.
The Bad:
No information on whether the weapon can be made masterwork or from special materials. Could you craft a Masterwork silver Spellstaff? No idea.
Inferior to the longbow, which is bad because they both require the same amount of investment to use, a proficiency feat.
Most casters wouldn't bother spending a feat to get longbow proficiency anyway.
The Ugly:
The Metamagic Empowerment feat is overwhelmingly powerful. In short: you could use a 2370gp Spellstaff to Quicken a 9th level spell once per day. Normally you must pay 170000gp to do the same three times per day, 56000gp per quickening.
No spellstaff related spells? No weird "Shrink spellstaff" or "Recharge spellstaff" or anything?
FaQ specifically states you cannot combine spellstaves and regular staves. WHY?
Potential modifications for your home game use:
Dont allow Metamagic Empowerment.
Spellstaff proficiency as a trait.
.
Final verdict:
Its definitely flawed, but this booklet is still worth the cost. It presents interesting ideas and enough rules to back it up in game. I will be inducting spellstaves in most of my home games, but with a few modifications. Think of this supplement as idea fodder rather then a source of groundbreaking new rules. Would reccomend for any staff fanatics out there.