I recently purchased a pair (excellent service from Yorkshire AV as ever) of Concept 50 speakers. I've been a life-long hi-fi follower and have been through many iterations of all sorts of equipment - from 'budget' to 'serious'.
I've upgraded from a pair of Concept 40 speakers, which have been relocated to the cinema room.
A few months ago, I auditioned a series of floorstanding speakers in the £3k to £5k range. The result of that was my intention to purchase the Concept 500's, acknowledging that they were a bit bigger than I wanted, but their performance was outstanding.
Note that my requirements include a room friendly size - ruling out may of the more substantial options (Quad Z4 for example).
I've noted some comments on the 'chrome' outriggers, but in reality, these speakers look superb in the flesh (mine are in the piano black and the finish is excellent) and the chrome is really not significant - if it is such an issue for some, then plastidip is the answer!!
Instantly upon installation, it was very obvious just how much of a step-up the 50's are compared to the 40's. Clarity and soundstage are a massive improvement, and that is before any running in.
I should disclose that I have a pair of bespoke stereo active sub-woofers (I know, often frowned upon in the UK hi-fi world but these are high end, 10" sealed units which are extremely fast, powerful and 'silent' in terms of integration). They transformed the performance of the 40's, and the same applies to the 50's, albeit the 50's are much improved on their own in terms of bass roll-off. I opt to use the foam port bungs (as they are quite close to the rear wall) which help to maintain control of the rear port behaviour.
I've not had the opportunity to audition the 50's and 500's together, but from my experience they have very similar 'house style' and the invisible cabinet signature; they seem closely matched in terms of upper and mid-range and soundstage, I'm sure the 500's had greater depth, but not a huge difference.
For the money, the currently available the last few Concept 40's for £499 are a steal. In my cinema room, with a matching Concept centre, they are amazing. However, the 50's are a massive step up and certainly feel worth every penny at a bit under £2k. The 500's were amazing, but they are bigger and still not less than £3.6k.
I'd recommend anyone in the market for svelte floorstanders in the £2k to +£3k range to audition the Concept 50's; from my experience they are the match for many alternatives which are up to twice the price.
Well done Q Acoustics, a real success.