Best Site Structure?

Right now, I use domain.com/xyz to rank for a local keyword. I want to restructure the website to start focusing on ranking the keyword for multiple cities.

What's the optimal way?

Domain.com/xyz-city/
Domain.com/xyz/city/

I'd rather have a general overview for the keyword on domain.com/xyz/ then have it link to the individual cities and start building off-page.

Thoughts?

Google and other bots understand structure, and hierarchy, I'd go the route of Domain.com/xyz/city , because it reads nice and easy, if it was for plumbing, domain.com/plumbing/newyorkcity would tell me all I needed to know, and if I can tell that fast, so can a bot.

It's all about relevance, doing it domain.com/plumbing-newyorkcity, kinda looks bad, like a directory or even spammy, plus are you going to have fun when you want to do another service, like domain.com/restoration-newyorkcity, will look bad, could even set it up like, domain.com/newyorkcity/plumbing... so when and if you had other section, can nest them under location, rather than service if there will be many. If there will be more locations than services, stick to original...

Check this out.

Search Engine Land: http://searchengineland.com/local-seo-landing-pages-2-0-222583

best site structure is in wordpress.

I've found that xyz/city works best, then use breadcrumbs to link back up the site. Works really well, you'll see it on most of those large sites that target multiple cities.