ahhh, thankfully there are car guys at anandtech.
Turbocharging doesn't hurt engine life, at least not oem ones anyways. (thats why a lot of oem turbos are used in aftermarket cars also superchargers like the eaton unit in buicks are used in many applications.) as long as your boost pressure is reasonable for your compression ratios, proper modification is an excellent way to increase gas mileage and power. The reason a lot of manufacturers don't use turbos is most of the time premium fuel is needed as well as higher insurance costs. Engines also run hotter, so you may have to change your oil more.
About turbo lag, it is prominent in some cars. Anyone remember the dodge daytona? 224 hp outta a massive turbo, and a ton of torque steer. But many cars have very progressive throttle response, including most of the lower pressure turbos, ie volvos, audis, and vws.