Optional!
I currently own and operate a top end performance LSA aircraft, the Dova Skylark, that is fitted with a rescue chute.
There are many more considerations than just cost and servicing.
You also have to consider the weight penalty, a fitted chute can add up to around 20 kg. As a percentage this is a fair chunk of our usable load.
In the case of my aircraft the chute is mounted in the nose. Once you have your head down in the foot wells to adjust / bleed brakes you become very aware that there is an explosive device only inches from your right ear.
Also when working under my aircraft you tend to be very concious of the exhaust tube coming out through the bottom of the fuse. Unlike some others, the manufacturers of the Skylark have put a duct in to direct the exhaust gases out the bottom so the cockpit does not fill with deadly gases while you float serenely down under your "rescue" chute.
Personally I also worry about the chute being pulled in panic. I know of at least one case in Europe where a chute was deployed by a paniced student during forced landing training in a situation where the instructor was perfectly comfortable. This deployment then opens up the possibility of injuries on impact ( remember they don't come down all that gentley ), it also does considerable damage to the airframe.
Another horrific scenerio is where a chute is deployed in panic with an in-flight fire. Remember that once the chute is deployed you are along for the ride, good bad or otherwise.
You must also consider the possibility of the chute deploying on impact in a forced landing or some other form of minor accident. This has the potential of turning something minor into a really bad situation.
Further to that senario, I do not imagine that most people ( professional rescuers or just the first ones to get to you ) coming to your assitance after an accident will be aware that your aircraft contains such an explosive device that may have had it's activation system damaged.
The popularity of rescue chutes outside of Australia I beleive is influenced by the differences in the terrain available for forced landings. There are few countries that have the open space that we have in Australia.
Personally I think the only senario where I would want to deploy a chute would be major structural failure. Realistically these do not often occur in an aircraft that has been flown with in it's designed flight envelope.
Having owned aircraft with and with out chutes, and having given alot of serious thought to the pro's and con's, I would rather not have one.