Here's a site that puts it in simple term:
180hp Lycoming - 4 jugs, less to replace or maintain, lighter
180hp Continental - 6 jugs, more reliable (or not), heavier
http://users.adelphia.net/~aeroengine/Chron4S2.html
Most guys go with the Lyco because it's less weight (and the plans cowl fits better ).
For GA applications, both are good and bad depending on the year and type. I know Continental had both a bottom or top oil resivoir, such as the bad rap on the early Cessna 210 (and the main gear thing).
Here's a quote for some argumentative firepower for all you rotary heads :
Continentals: Cylinders crack, barrels crack, sparkplug holes crack, exhaust port at valve guides crack. Cranks crack and counterweights come apart. Light cases crack. Starters can be a nightmare.
Lycomings: Eat up exhaust valves, piston pin plugs come apart, valve lifters are horrid, camshafts are the luck of the draw, rocker arm support bosses crack thru fall off, cases leak like a British car. Pushrods bend. Oh and then there are the light flange cranks and light cylinders. Klinkers can turn off all the fire in the cylinders quick.
I have seen both makes of engines go to TBO spotless, and others not make it half way with a Top Overhaul to help.......Why........ the OPERATOR and MAINTENANCE. (oops! I did not mean to yell so loud )
http://rawlinsbrothers.org/bhfaq/lycvcont.html