On my 100, after the update the other night the channel changes have become really long. It was not even noticable before and now its like 5 seconds with the occasional channel not coming in at all (stays on black screen) and if I change the channel and go back to the same channel it comes in fine after about 5 seconds. Im using component on a 1080i tv with 1080i selected and native off.
I had a similar experience - also with an -100. I didn't time it specifically, but I really noticed the problem after the most recent (this week) software update and after I checked the "test" channels in the upper 400s. All channel changes after I did that seem to take around 10+ seconds. I did a menu-reset and the change time improved. It still seems a bit slow - but I can't really remember if its slower than before the software update or not.