I have both and although the Swit batteries are good for the price, the original Panny ones last significantly longer. Unfortunately I can't tell you exactly by how much as I haven't measured it but I know that next time I buy batteries I'll probably put the extra $$ to get more time...
They were only about $25 apiece including shipping, and they seem to last about as long as the Panasonic one that came with the HVX. Can't say yet about long-term durability, but IMO they're pretty unbeatable for the price.