During cardiac catherization, if blockage found, which best to use to open the blockage:balloon or stint, cons and pros please?

Stents. Provided that the anatomy is favorable for such. Stenting keeps arteries open longer....Disadvantage is need for Plavix (clopidogrel) after which is generally far outweighed by benefits.
Depends. The blockages found during cardiac cath can be treated with stents or surgery. No one really does balloon angioplasty alone anymore. The decision between stents and surgery depends on how many arteries are involved, how bad the blockages are, whether the left main artery is involved, how bad the left ventricular function is, and if the patient is diabetic or not.