I've been accused on more than one occasion of being a QuickLOAD shill, but it really is a terrific program that provides information available nowhere else.
Is QuickLOAD perfect? Well... no. But I've not found much perfection in my 54 years on this lovely orb, so that criticism doesn't bother me much. Is it useful? Most definitely. It saves me a lot of time when working up a new or unusual load.
QuickLOAD is missing a few commonly-used powders (Trail Boss, all of the IMR handgun powders, and HS-7), but it does cover the Accurate, Ramshot, and my beloved VihtaVuori powders completely (as well as almost all of the Hodgdon powders). Updates come out about every year or so for a very nominal fee (about $15 if I remember correctly). But I've only purchased updates when there was some burning need for a specific powder in the update.
Some of the data in QuickLOAD also seems a little off for Power Pistol and AA #2, at least in my experience (it may just be a lot-to-lot variation thing). What I've found is that, for every cartridge I load, if I very carefully measure the actual water capacity a case will hold and then average this weight over ten cases, the numbers the program computes are much more accurate. Consequently, the only "mixed-brass" I now use is in .380 Auto, and I'm getting ready to retire that group of cases.
Where QuickLOAD really shines is in helping to solve problems for which there is no readily available information. Here are two examples...
First, I want to load a heavyweight lead bullet in .44 Special without exceeding the SAAMI maximum average pressure. QuickLOAD was essential in telling me that I could do it safely and efficiently, and that the best powder for this task might well be VihtaVuori's N105, a powder I'd never considered previously. Initial testing is very promising.
Second, I want to load an efficient .357 Magnum round with 158gr bullets at "tweener" velocities (between .38 Special +P and full-bore .357 Magnum pressures). QuickLOAD has made that task a piece of cake. It's also fun to run "what-if" problems using bullets of 140gr and 180gr under the same scenario.
I could go on and on about QuickLOAD (and you may think this comment has done that...), but is it worth $150? I don't know about you, but it sure has been for me. YMMV.