The difference between medicated and non-medicated stents is that the re-blockage rate in the early phase of medicated stents is less and in that sense, the medicated stents last longer than non-medicated stents. However, after 6 months the results of medicated and non-medicated stents become equal. That is if the non-medicated stent has not blocked in the first six months then its chances of getting blocked subsequently are the same as that of a medicated stent. Chances of stent collapsing or the artery getting to rupture are very small and in fact less than 1%.
Bypass surgery is suited, when there are multiple blockages or the blockages involve multiple arteries or when the blockage is long segment block, a heavily calcified block or there are other technical considerations which makes angioplasty a less suited option. The cost of angioplasty and bypass surgery is not the same and in multiple vessel disease, angioplasty turns out much more costlier than bypass surgery. Majority of these decisions are technical decisions and are taken by your doctor in charge but within informed discussion with the patients.