I can't really list 5 specific, but I found when considering this thread that I had my opposites come up when I had thought about (but not posted in) the other thread regarding the top 5 IDW things.

Such as:

My favourite comics were 'All Hail Megatron'
My lest fav were the Optimus ones from the last few years

My fav relationship was Rewind and Chromedome
My least fav was Onslaught and Blast Off

Some of the comics had the best art I've ever seen in a TF comic
Some of them had the worst I've seen since the 80's

Some minor characters became awesome like Swerve
Others reached a new level of annoying like Slide

There were great new concepts introduced which I reckon should become lore
Some of the previous lore I loved frankly got spat upon



So yeah, my favourite things about the IDW run seemed to have their polar opposites.