I would definitively recommend an alternative: DreamFect Gold. It is indeed a lipid-based transfection reagent, but highly efficient and biodegradable (high viability).
you can refer to : http://www.ncbi.nlm.nih.gov/pubmed/21248078 for more details,
do not hesitate to contact me at [email protected] if you need any information
C2C12 cells are undifferentiated cells so any commercial mammalian transfection kit should work. These are relatively easy to transfect compared to hard to transfect cells like macrophages for which we use specific transfection kits. Lipofectamine, genePORTER all will work.
I agree with the usage of lipofectants like lipofectamine 2000. Back some years ago, we also used precipitation with calcium/phosphate with fair performance. Good luck!