Quality of inbound links to website as well as guantity of inbound links is very important to Google Maps rankings. What is quality inbound links? In this case, it is related to geo-specific links. The quality and quantity of inbound links with the right anchor text will just possibly overcome everything else in doing well in Google Maps.
For other local search, visit our Google Maps Algorithm page, Google Maps Optimization (Google Maps SEO) page, Live Search Map and Yahoo Local page.