I had a ZAGG screen protector on my Touch Pro. I never really noticed it getting yellow but when I took it off after a year (had to replace the phone) it did have a yellow tint to it. The nice thing about it is that they will replace it for life so if it yellows after 6 months just have them send a new one. I think there was like a $3 shipping fee and you have to send the old one back within 30 days after they send the new one.
I ordered one already for my new EVO and they were nice enough to email me today with two 25% off discount codes. If anyone wants them (they are one time use only and first come first server)...here they are:
use this link:
http://bit.ly/9aEwKX
Use one of these two codes:
is6sfa4p
isbsfas9
If you use one of the codes, please post that you have used it so others will know when both have been used.