Soulwars and experiments are about the same amount of exp per hour (soulwars might be faster) except experiments include hp experience too.....
In the end soulwars is faster especially if you use 100 zeal.
Souldwars is much faster, as verac mentioned, also a bonus of soulwars is it has a verylow ban rate and you can run i for longer without risk of a ban. If you want hp raised though, experiments is good.