Having got this monitor, I would say this is a fair price. It's not the best for gaming (as has been noted), and there are of course monitors with better colour accuracy, but not at this price level!
I picked up the AW3420DW for ~£610 but that was probably a one off. It depends what you need it for (gaming/photo editing/home office use). I'd suggested that this U3419W would be a very good photo editing and home office monitor but you could get a better gaming monitor for less (https://www.overclockers.co.uk/iiyama-g-master-gb3461wqsu-b1-34-3840x1440-ips-144hz-1ms-hdr-freesync-ultrawide-gaming-monitor-mo-13j-iy.html).
I did like the look of the AW3420DW, but £1100 just seems like quite a lot more for higher refresh rate and g-sync. You also lose 10 bit colour, and the built in KVM, USB-C and multipicture capabilities.
I think the Dell Alienware UW's are a better deal and if you wait you can pick them up for this price. This is expensive for a 60hz monitor.