I've used fusible interface, and it's awesome. I think the problem with it is people don't shrink it or the fabric to fit. You have to pre-shrink the fabric (wash and dry) and then get the fusible interfacing wet, and let it air dry. VERY IMPORTANT! If you toss it in a dryer, the fusible (glue) side loses it's glue, and it messes up your dryer and everything inside. If you shrink the fabric and not the interface, when the garment gets washed the interface shrinks and puckers the fabric it's sewed onto.
But (with the limited amount I know) with fusible interfacing, after both are washed and dried out, you baste it in first, then steam it, rip the baste seam and then do your final stitch.
If bubbles come up from it after, it wasn't pressed good in the first place. It needs heat, pressure and steam to seal. Get a piece of scrap fabric between your iron and the actual piece too, because when done right, the interface glue oozes out of the sides and f#cks up your iron face. Once it oozes out and cools down, try to pull it apart to test the seal.
Interfacing is usually on little things like collars and cuffs, so if you burn it or tear it, it's better to be safe than sorry right?
Oh, and when I cut interface, I tack it to the back of the fabric like so: v v v with an iron to stick it on before I cut it from the pattern. My teachers are horrified when they see it, but the pieces come out perfect because I cut them out as one piece. And it's inside, so who cares?