It's still fairly new, AFAIK only Tikka/Sako chamber for it currently. It looks like a good round, but lacks any real 'glitz' so it will probably go the way of the 358. Which is a real shame, as the 338-08 should be about perfect for the needs of most typical hunters, but they'll probably buy a wizzum instead. (not that there's anything WRONG with a WSM, I personally like them but I also acknowledge that they're probably more cartridge than is truly needed most of the time)
By all accounts, the factory ballistics are somewhat 'optimistic,' it is essentially to the 338-06 what the 358 is to the 35 Whelen or the 308 to the 30-06; 100-150fps behind with 'standard-weight' bullets.