Hifi.nl has tested the OPTICON 5 and finds it special in every way. It is not like the regular floor-standing 6’s and still much bigger than the usual OPTICON 2's, which is often found on the bookshelf. And the OPTICON 5 is indeed special, not only when taking the size into consideration, but also when it comes to the sound performance. Their verdict is that the OPTICON 5 is definitely worth a listen due to their great musicality, wide sound image and outstanding mid-range.
The full review is available here (in Dutch).