My issue with the oil/liquid type lubricants stems from the oil dents and wrinkles I get when forming .222 cases from .223 and 5.56 brass. If you get just a small spot that is applied too thick on the neck/shoulder area, you are sure to have a oil dent or wrinkle. I found when forming with either a FL die or a Form/Trim die that I would have to size in very small increments and continually wipe off the neck/shoulder area or I would ruin cases with oil dents and wrinkles.
With Imperial the stuff is just so slippery that it only requires an extremely thin coating, and is much easier to apply extremely thin as it's a wax, and not an oil or liquid. It just feels so much smoother in the press handle, especially when using a FL die with an expander, as I often feel a grabbing when the expander is passing through the neck with the others. Just a small amount (of Imperial) on a Q-Tip wiped in the neck makes the expander just glide on through.
I have however found a lubricant I feel may be just as good as Imperial, and at half the price as well. (not that Imperial is super expensive, but anytime I can cut the cost of a product in half I'm happy) It's called Sharp Shoot R Royal Case Sizing Wax. (http://www.midwayusa.com/viewProduct/?productNumber=623016) I have only been using this stuff for a short time, but it seems to work just as well, though it is a bit lighter in consistency. You still only need as very small amount, and cases size like they are made of warm butter.
The Hornady Sizing Wax will likely be very similar as well, and I would try that long before any of the oil/liquid lubes.
And as I stated earlier, the Lee Case Sizing Lube works great for general sizing, and is awesome on most pistol cases (excluding very large or hard to size calibers) when thinned with rubbing alcohol (or even water) and sprayed on. It's also super cheap and easy to find.
Lee Case Sizing Lube is actually the same lube used by an auto manufacturer for their deep-draw stamping and other such forming applications. If it will hold up to deep draw stamping on a 40-ton press, sizing cartridge brass will be a cake walk.
The only downfall is that the Lee Lube is water based and will dis-color cases if not wiped off thoroughly soon after sizing. Other than that, it works great.
If you want the best for precision sizing and heavy forming, Imperial or Royal Sizing Wax are the way to go. If you want a versatile lube that can do it all, from forming and full length sizing, and even be thinned out and sprayed on, than Lee Sizing Lube is worth a shot.
For the best and most complete lube set-up ready for whatever the loading session brings, one of the waxes (Imperial or Royal), the Lee Case Sizing Lube and a neck graphiter (http://www.sinclairintl.com/.aspx/pid=33148/Product/Imperial_Application_Media [OR] http://www.sinclairintl.com/.aspx/sid=65732/sku/FORSTER_Graphiter) will handle whatever you throw at them.
You could even add a lube pad for use with slightly thinned Lee Lube, as I have done so in the past with good results. Just dampen the pad with a spray of water if it starts to dry out and add a bit more lube and it's good to go.