I've been working on and running ERP delivery programmes for the last 15 years across SAP, Oracle EBS and a few others, and my opinion is that as a product SAP is (in a very Germanic way) overly fussy and needlessly complex. It sacrifices efficiency and speed and usability for "completeness". The move from separate R/3 apps to a more joined up underlying infrastructure in ECC made it slightly better from an integration perspective. Their licensing model is an absolute maze of hidden costs which unfortunately does seem to mean that a lot of projects software and OPEX costs overrun simply because nobody really understands them - and because they change so often. And yes, SAP product development vs product marketing does seem to be somewhat disjointed (to put it in a civil manner).
I think it's unfair to say the software is crap though because when it works, it works quite well from a technical perspective. And as I've said before on these hallowed El Reg boards, most ERP projects overrun not due to the underlying software itself, but due to incomplete business process analysis and requirements specifications, that, and a lot of larger 3rd party integrator being (A) shit generally, (B) promising more than they can deliver, or (C) bidding lower simply to win the work - and the client bean counters not challenging them.
That said, Oracle EBS is no better. I've actually worked with some free open source ERPs that do a better job than either of them.