IMO, the Swede is a handloader's cartridge. Yes, there is factory ammo for it, but even the best factory ammo does not reach the full potential of the 6.5x55. Where factory ammo is concerned, I have been impressed with the Hornady Superformance 140 SST load. The Prvi Partizan stuff is a good choice for plinking/barrel break-in ammo and will leave you with good brass to reload.
I believe the best option to be loading your own for the ol' Swede. Buy the dies of your choice (I like and use Redding dies, but there are plenty of other good choices), Lapua brass, and whatever bullet suits your fancy. For most things, I prefer Berger 140 VLD's and Hornady 140 AMAX's. If I were to ever consider using the 6.5x55 on elk sized critters, I would go with the 140 Nosler Partition. The 140 class bullets have all shot well from my 6.5's with 9 twist barrels, but an 8 twist is still a good idea.
So far, my best load has used H4831 and Berger 140 VLD's. RL-22 and RL-17 are also excellent choices.
In a modern action, made with modern steel, the 6.5x55 will outperform the .260 Remington and come very close to the 6.5-284. Among my 6.5's, I have a 6.5x55 and a 6.5-284. I consider the latter to be much ado about nothing. It is being re-chambered to .264 Winchester Magnum. The 6.5x55 exceeded my expectations. I would take it over any other non-magnum 6.5 and have a second one being completed in a light sporter configuration.