I have the original Predators that take the 4 round rotary magazines in both 308 and 6.5 CM. I like both cartridges and the rifles enough that I bought another 308 that takes the new AI magazines and plan to sell the older 308 that uses the older style magazines. I wouldn't buy that version again, the AI style magazines are that much better. It comes with a 3 round mag that doesn't protrude below the stock enough to be an issue.
Ruger and Magpul sell 5 round mags for $34-$39 and I don't find them to protrude far enough to be a problem. The Magpul magazines have a tab that you can cut off to increase mag capacity to 6 if you want, or leave it at 5 for locations where 5 is the limit for hunting. Ruger also sells a 10 round mag. They are starting to get a little too long for my taste, but I bought one anyway.
The rifles serve different roles for me. The 6.5 is more for precision shooting at longer ranges. I wanted to buy something in 6.5 CM just to see what the fuss was all about and felt the Predator was the cheapest way to get into the cartridge with a rifle that would still be accurate enough. I like the round and it does everything 308 does better. But I wanted the shorter more compact length of the 308 for brush hunting and that is way I opted to buy that version that takes the AI magazines. I get equal, and excellent accuracy with both. I contacted Ruger via e-mail about simply buying the new stock and they wouldn't work with me, but I've read of others who have done so. I may call back and try talking to someone in person and simply replace the stock on my 6.5. The same mags BTW work with 308, 6mm CM, 7-08, 6.5 CM and 243.
The barrel twist on the Predator in 243 won't work well with heavier bullets. The 6mm CM barrel will. If considering 243/6mm keep that in mind. The 243 version will be easier to find ammo for and should be fine with bullet weights under 100 gr. If you want to go with the longer 105-108 gr target bullets you want the 6mm Creedmoor, but you'll need to hand load. There are plenty of good factory loads at reasonable prices for both 6.5 CM and 308. You can find plinking or surplus 308 ammo cheaper, but the price is about the same for the good stuff.
If you like 308 don't let the shorter barrel scare you off. 308 doesn't give up much from shorter barrels. Mine with an 18" barrel is about 60 fps slower with the same ammo as my 22" barreled 308's. I posted a photo of my older 308 Predator in the brush gun thread. I don't have a photo of the newer version yet.
On aftermarket stocks B&C is now offering a synthetic version. Currently only available for long action sporters, but I expect more versions eventually. I'm not a fan of plywood stocks, but might consider one of these down the road.
http://www.bellandcarlson.com/index.cfm?fuseaction=category.display&category_id=1137
