Should I buy the Canon A495 or A490?
Do they both have the same CHDK features? Will I be able to put an intervalometer script and shutter speed to both of them or which one?
I would suggest you decide based on comparing the cameras without worrying about CHDK. From what I can see the A495 is a better camera. CHDK features should work pretty much the same on both. However, it would be good to also read through any forum threads for either camera to be sure. Can't speak for the A490 but I believe all firmware versions that have been reported for the A495 are supported.
I am a little scared to put CHDK on those cameras because on http://mighty-hoernsche.de/ they both are "BETA". Does that mean they lack the resources? I just need to intervalometer and shutter speed adjusted?
The BETA status you see is somewhat arbitrary. Some beta releases are purported to be in better shape than some full releases - as each camera has generally been ported by a different developer and there is no standard definition of what is or is not Beta, you cannot read too much into the description. In general, things tagged as Beta will load and run but every little detail of the more exotic functions might not have been completely tested.
As always, if you get a camera that has a supported version of CHDK for its firmware, you can probably find help here on the forum for anything that might not seem to work quite right.
I would expect intervalometer and shutter speed adjustment to work just fine for both the A490 and A495. But if you are stuck for an answer - buy the A495 due to more firmware versions being supported.
