Hey Dave,
My recommendation would be if your clients end up with 100+ locations or more, maybe you should look at Yext. The onboarding is much faster. If you can take your time with the clients, then do it manually. Because at the end of the day the annual cost is a killer on Yext.
I know Yext tries to really highlight they do coupons, menus, etc. but those features are superfluous in my opinion. I'd actually be interested to see how often a coupon offered by Yext on the directories they submit to actually gets used. I'd bet it's zero. And who is looking at a menu on a directory? And if they are, it's probably Yelp or something similar that you can just do yourself quickly. In the amount of time you upload menu information to Yext you could just upload directly to those bigger directories.
On hours, I've never really considered this an issue. We always do manual (we own Local Listing Ninja of course) and just tell people to change their hours on Google, Facebook, Yelp, Facebook and Yellowpages if you want. That's going to take care of 99% of people looking for your hours. In my opinion, there's no reason to use Yext just for the hours. Just me though.