I've been using NTI 5.x for a long time.
For data and audio, it has been rock-solid and never created a coaster.
But, IMHO, version 6.x is too big for my taste and looks like a "skinned" version of the early v5.x.
Since I don't own a DVD-r drive, I can still stick which version 5.x.
To burn non-ISO images, I commonly use CDRWin, CloneCD or an old version of Alcohol(I had problems using the later version).
NTI CD Maker looks funny or even weak to people acostumed to other burning proggies, but its burning engine is considered by many one of the best on the market.