Upgrading to Yamaha RX-A1010 or Pioneer VSX-LX55 - Advice Wanted

Hi folks

I'm after a bit of advice re upgrading current AV set up. I have a Denon AVR-1910 which in my opinion sounds good. Minor problem with the amp is there is a persistent problem with the handshake between blu-ray player and True HD Sound. Not a major problem but annoying nonetheless as it completely loses sound only sorted by repeatedly re-selecting the source..

I've been toying with the idea of upgrading my AV receiver for a while to either the Yamaha RX-A1010 or Pioneer VSX-LX55 both of which get excellent reviews. My current speaker set up is Kef HTC/HFS 2001.3 with Kube 2 Sub. I've also a pair of Kef Q Series IQ55 giving me a 7.1 set up.

My question is would it be worth the investment buying the Yamaha or Pioneer amp. Given I'm not currently changing my speakers will I notice a worthwhile difference from a new amp and would be worth the £850/£1000 investment?

Any helpful comments would be appreciated. 

Thanks

Simon