Help with true differnce between 60Hz and 120Hz (long)

[unmach]

I am deciding between the same two HDTV's, same model and manufacturer. One has a 60Hz refresh rate, the other 120Hz. There is a considerable price difference, which is okay if it is worth it.
I found that 120Hz, devisable by both 30fps and 24fps, is supposed to make films very smooth. In direct contrast, I ran into two seperate reviewers, recommending turning off the 120Hz to 60Hz during movies.
So which is it, good for 24fps films, or bad?
Also I heard unconfirmed posts saying the extra processing to do 120Hz can cause lag, the last thing I want.

My uses for the tv will be Xbox360 and PS3, along with blue ray movies and HD cable service through directv. I really want the most clear smooth picture I can get, so I am plannng on the sony bravia XBR 1080p. but I really don't know about 60 or 120Hz.
Is it worth the price, meaning is there any noticable difference? How much? And is it true at all that changing from 120 to 60Hz for movies is better, despite the opposite being advertised?

I know this was long, but this is a huge investment for me, and I want the best I can get. But if the 60Hz version is scarcely different, I would gladly save 700$ and purchase it.

Thanks for reading all this, and thanks a lot for any replies you may have

 

[rexter]

http/www.avsforum.com/avs-vb/showthread.php?t=942365

The only way to tell is to see it in action and ask the sales person to switch the freq from 60 to 120 Hz using different sources. Then you deside if it's $700 worth of technology.

http/en.wikipedia.org/wiki/HDTV_Blur

http/www.avsforum.com/avs-vb/showthread.php?t=997138

 

[unmach]

@Rexter
Thx for the links, I didn't even know what interpolation meant until now.
I don't have a store within 60 miles to go watch a demo by a salesmen, but from what I hear 120Hz looks great.

My only lingering question is about lag. Will the processing time of the motion interpolation create lag on high speed games or movie sequences?

Thank you for your time.

 

[rexter]

New units comes out every year if you’re not sure about what to get is you wait a little bit longer 'till you find something you're comfortable getting, but for some it's either get it now or forever wait for something better. As what we want is not what we actually need and what we can afford.

Trust the professional reviewers (there's plenty of them out there) as they already compare some equipments, then read the users review once you selected a particular units. The list on avsforum mentioned earlier is a good place to start.

 

[jt001]

I would say it's probably not worth the extra money. There's no real 120Hz sources and I don't see any coming anytime soon, and if there's lag in the processing of it then it defeats the entire purpose of a higher refresh rate. Also, an 120Hz LCD for example may take that refresh rate, but because of the response time likely wouldn't actually give the full benefit, not sure if this would apply to other TV types.

The only real benefit is the fact that 120 is divisible by 24, but there's already pretty good technology to deal with this on 60Hz screens, so I don't think that really would matter much. I personally wouldn't even consider a 120Hz screen considering the huge price difference.