I use electronic-type sidecutters (dykes). They're available at any electronics store for about 7-10 dollars, cut right at the tip if you need 'em to, (they're designed to flush-cut metal leads on components like diodes and resistors soldered to pc boards), and I mean they cut close... You can cut a wire lead with the first .5mm of the tip, they're angled at about 35 degrees, and they have a small notch for stripping wire... Cutting styrene isn't any problem for 'em.. I've had them for about 30 years, and never once did I consider getting anything to replace them from a hobby shop... Too many tools in hobby shops are actualy designed for other uses, but a manufacturer changes the label to include the word "Modeling" on it, and they can tack another 15 bucks onto the MSRP... Phooey... If you damage them, then you're using the wrong tool for the job at hand, and likely fall into the category of those that'll use a pliers to drive in a nail... If you have a problem with "launching parts", you ain't usin' em right, you're cuttin' to far into the jaws... Use the first milimeter of the tip...
A tool as basic as a sprue cutter for modeling shouldn't cost more than a couple cans of spray paint... Ever...