I read this thread with interest. Personally I wouldn't carry anything I haven't had a chance to try out with a sparring partner. Objects that seem good swinging around in the living room have sometimes proved to have significant weaknesses in actual sparring.
I have an extensive amount of experience with inexpensive (i.e. $8-$12) bokken, and these over-the-counter weapons vary significantly from specimen to specimen. Buying "sight unseen" from online retailers is a crap shoot, and unfortunately it isn't easy to find an actual brick and mortar martial arts store these days. I could go more with more expensive bokken, but they get used, abused, and destroyed, and I'm not looking for a display piece.
The result of my experience is that I've had a chance to try bokken of widely varying weight, thickness, and density. Unsurprisingly those that appear to have the best grain often last the longest. Still, most begin to splinter along the blade after a few weeks, and I've often had to discard an otherwise okay bokken for fear of depositing splinters in my sparring partner's flesh. If the grain cooperates then sanding sometimes helps prolong the useful life of a bokken.
Then of course there are the specimens that simply crack or shatter. I realize these results are due to poor techniques that do not reflect the true nature of Kendo, but I've never claimed to be an expert swordsman. Because of this, I was eager to try Cold Steels relatively new polypropylene bokken. While they handle completely differently than wood, they do seem to be almost indestructible, and duplicate the feel of a live blade a bit more. It is more difficult to parry with a Cold Steel bokken, as they do not have the mass to simply push away an incoming strike. However, with both partners armed with the same weapon, this only means that techniques have to be modified to reflect the characteristics of the tool.
All of this being said, I would carry either a hardwood or polypro bokken with confidence. Having been the victim of perhaps hundreds of failed parries, I am well aware of how easily they can put an end to either the fight or at least one's willingness to continue resisting. The Cold Steel bokken hurt just as much, but don't tend to bruise as badly, and with less mass I would have to go with hardwood, but either would be effective against an opponent of lesser skill or armament.