SOG just recently upgraded the PowerLock, adding gear covers and an improved pliers. If you end up buying the SOG, I'd recommend getting the new one. Here's a link to my review:
http://www.bladeforums.com/forums/showthread.php?t=505065
Here's a quick comparison of the pros and cons for each:
SOG PowerLock
* Best Pliers (compound leverage)
Pros
• Compound leverage pliers
• Pliers open one-handed
• User serviceable and customizable (order parts direct from SOG)
• All tools lock
• 1/4" drive adapter and optional adapter fit standard hex bits
Cons
• Typical configurations lack a plain edge blade (available as a replacement direct from SOG)
• Blade edges face the middle of the tool
• No one-hand opening blade
• Tool clumping
• Access to tools requires opening the pliers and a cover
• Adapter fits loosely
Victorinox SwissTool RS
* Best Tool Selection (I actually prefer the SwissTool X over the SwissTool RS)
Pros
• Excellent tool selection and design
• All tools lock
• All tools accessible from the outside
• A bit driver is available as a package with the standard SwissTool (SwissTool Plus) and can also be purchased separately (could be used with any multi-tool)
Cons
• Not user serviceable
• Lacks file (SwissTool RS)
• Pliers a bit blunt compared to the needle nose pliers on the SOG
• Screwdrivers have rounded edges and are more prone to slipping
• Heavier than the SOG