If this helps at all, I would say that on a purely visual basis, Strains to me are like the coupes of Indy whips, while Jackas are the SUVs. The former is sleek and fluid, while the latter is bulky and takes some musclin'! Both are screen-used and screen-accurate, although the Jacka gets more screen time (think of Jacka as the action movie star, while the Strain would be the stunt double).
Though I own both, I only use my Strain mainly due to the weight, but also due to the cost. Since the Jacka costs a little more, and was a lot more trouble getting in here, I plan on using it exclusively as a display piece. Which is hard to do, because it REFUSES to coil, even after half a year!
I've read that the only way you can get it to coil in that perfect, tight 'O' is by actually using it to get it broken in, but since I won't use it, I'll have to settle for it being a 'G'!
And lastly, I don't know if this matters to you at all in deciding which whip to get, but like I hinted at above, I'd say the Strain is the faster whip to get, although I don't know if that's still true today. When I ordered my Strain, it got here a couple months later, while I had to wait for my Jacka for half a year, due to the demand. Also, Strain is based in the US, while Jacka sends his out of Australia, so you'll have to contend with export permits, and a bit of a longer shipping time.
