So, I have a little bit of professional experience with both the plated and powder coated bullets so I will tell you what I know. I can't say much about the Hitek coating though as I have no experience with it at all.
Powder coating is extremely pretty, quite slick, cleans up easy, and is very very very hard to do right. The biggest issue you will get with powder coating is an inconsistent coating over the entire bullet. Even though the entire bullet may look perfect and pretty, you could end up with a jacket that is .020" thick on one side of the body and another that is just .005". If this happens, your bullet will want to fly wobbly and it won't always hit your point of aim. This isn't as big a deal in pistols as it is in rifles, but it may explain why rifle bullets that have been powder coated are never as accurate as gas checked rifle bullets even though there doesn't appear to be anything wrong with the coating after firing. I'm not saying it can't be done to give a perfectly concentric coating, just that it is nearly impossible. That said, this hasn't stopped me from spending a lot of money to find a way to do it in a what that should be "good enough." I think the benefits outweigh the cons with coated bullets.
Plated bullets suffer from the same issue because various shapes and angles will attract the copper differently. Plating thickness will vary over the entire surface of the bullet and the copper tends to accumulate the most around the edge of the base. The variances are much less than that of powder coating so a reasonable amount of accuracy can be obtained. That said, not all plated bullets are created equal. For example, if you take four different brands of plated bullets, you will get four different standards of plating thickness (e.g. .006"-.016") Also, between each caliber and grain of each brand of bullet you will find different standards for plating thickness as well. Most plated bullets are made out of the softest lead they can get that will still work in the core cutters. This is usually even softer than jacketed lead cores. Some people experience bad bullet setback or even bullet resizing during seating because of the super soft lead core. In my experience, the resizing of a plated bullet can often be traced back to a Lee FCD. The soft lead will also obturate too much at higher velocities and the thin plating will crack and fail. This isn't a huge deal unless you are trying to push the envelope on speed.
Now, if you don't want to be exposed to biased information please stop reading here. Though this may construed as trying to advertise, it is more intended to explain that not all plated bullets are created equal. Too often, plated bullets get lumped into a single category when really each plated bullet should be given its own category and special treatment. Berry's, Rainier, Frontier, Xtreme, Powerbond, RMR, and Speer all have different plating thicknesses, core harness, and varying quality and each one may need to be treated differently.
For example, we have our own line of plated bullet that we developed based on the various issues we've seen with other plated bullets. The first thing we started with was a much harder lead core. The hard lead core does a number of things for the bullet. Coupled with our thick plating of between ".011-.014" It seems to handle higher velocities just fine. It also resists being resized during the seating and crimping stage. Our bullet also seems to resist bullet setback which we attribute to three factors. One is the harder lead core doesn't allow the bullet to resize while seating, second, we size all our plated bullets to what a commercial hard cast bullet would be so there is more neck tension, and third, we purposefully don't polish our bullets to a mirror finish so that it isn't so slick. We actually found that highly polished bullets may be very pretty but may have something to do with variances in seating depth and bullet setback. That isn't to say our bullets are ugly, just that you won't be able to see your face smiling back at you while you load them. Third, we put our bullets through three different striking processes. First we make the lead core. Then the core gets struck to the proper diameter for accepting the determined plating thickness. This is supposed to help with concentricity of the copper coating. The bullet is plated in two steps which creates a lot of excess copper on the base which is, when struck again, folded over onto the base creating what we have been calling a gas seal. Finally, the round is struck for a third time to make sure every one is the right diameter. A lot of extra time and materials goes into making our bullet. Because of this, I think our bullet will stand up to most any jacketed bullet in both accuracy and loadability. Not all plated bullets are the same.
I use powder coating now for almost all of my cast loads, but I'd have no trouble going back to hard lube or Tumble Lube. It's the balancing of the hardness of the lead, the lube and the load to ensure as little leading/fouling as possible.
