I've been selling in Oak Park since 1991. I occassionally take listings out of the area but only for long term clients and I let them know that this is not my area of expertise. They already know that of course.
Rember, it's always the little things that could hamper you if you don't use a local expert, not just a local agent. An example...Hosting Broker Tours on the right days and at the right times. Believe me, most Oak Park agentsfeel like it is their God given right to have your listing. If an out of area agent hosts a Broker's Tour in south Oak Park in the afternoon time slot, the local agents won't drive ALL the way to south OP to preview it. Same if they host north of the tracks in the 9-11 slot. It's ridiculous, but it's true.
Most out of area agents do not grasp the differences in pricing based on location/school districts.
Homes on the east side of Euclid are in Irving and on the west side of Euclid are in Lincoln.
Same thing with homes on the 1200 north, 8 and 900 south and along Madison that don't sell for as much based on location. I don't know the ins and outs of Hinsdale or Burr Ridge etc., city agents and LaGrange area agents don't know Oak Park's inticacies. I realize most agents in the city cover wide geographic areas as do agents in the Western Suburbs. However, OP is different, no for sale signs, no directional signs for Sunday Opens etc.
If I were looking for good criteria for a listing agent, ask her/him to give you concrete data for the last four years showing their listings with initial list price, last list price, sale price, percentage of each and days on market for all of their listings.
In Oak Park, the Wed Journal also runs special advertising only for members of the Oak Park Area Association of Realtors offices.If you list with an out of town agent you will never be in the special section for the "Saturation Issues" which are delivered to every home, regardless of subscription, once a month.
Given all that, if your agent is a good, and I mean very good, top 5% of their board etc. then you will be alright. If they are a middle of the road agent, one that is not feeding their family with their production..., then I would be hesitant. Single family units were down 6.5% in 2007, days on market was 25% longer and prices only went up by 2.4% Make sure you give yourself your best shot at being successful.