I purchased the UK Classic Transformers - only to wind up selling them later, frustrated with IDW's release schedule.
I concur with you regarding the printing - they shrank the original content to find within the confines of standard American comic. I assume, as I have not had the access to Titan's preproduction, the resizing was an attempt for IDW to save on overall production cost (ie bigger comic, more paper). While I personally found the resizing befuddling in the beginning - I came to appreciate the extras and recolorization, and the resizing did not bother me when I received the second trade.
What bothered me most was IDW's release schedule. I was very excited to read Furman's stories leading up to the Unicron saga that was printed in the US Transformers comic. IDW would solicit a TRANSFORMERS UK CLASSIC trade to be released in Nov. 2012, only to be released in July 2013. TF UK Vol 5 was originally scheduled for a mid-late 2013 release, and of August 2014 - they have not released said trade. The release date keeps getting pushed back.
Are they trying to obtain more orders by delaying? I have no idea, but the delays frustrated me as missed released dates kept creeping along every two weeks, I simply stopped collecting them. I have been reading UK collected editions through my library's interlibrary loan program.
While I dig many of IDW's products - they lost a customer for UK TF