So just to clarify a couple of things, if you pay the £99 the router is yours. You’re not renting any hardware 
The reason we chose that specific router is, it’s cost effective for customers, but it also has what we feel is a very, very crucial element of the 2.5Gbps LAN so you can take full advantage of the speeds (if you’re looking at buying another router, you may find a lot of them don’t come with a 2.5Gbps LAN only WAN)
I honestly (happy to be proven wrong) don’t believe you’d find a router with the capabilities of the EX820v for cheaper