i have tube vitalizer, it works great, sound quality is top, but you have to use it carefully, especially on master. it is more on the soft side, it doesnt work too good with agressive sources, but on acoustic music it can make wonders. it gets used a lot on separate tracks (backing vocals, percussion, acc guitars...). for mastering i apply just a little of its processing and i almost never use comp/limiter or bass enhancer.