If you're entitled to the "pods" free, they are probably well worth waiting for - they represent a far better system than the crappy old powerline boosters VM used to dish out, and (in theory) you're getting a product that's almost fully integrated with VM's hub 3 and 4 (although carelessly the VM Connect app still doesn't seem to work with them), complete with support.
As @tehwolf says, if you have to pay for them, that £5 a month mounts up. In eighteen months you'd have paid as much in rental as the cost of a decent mesh wireless setup that will give better coverage, and of course you'd own the mesh. Personally I also think there's also advantages in providing your own wifi gear because it means NOT having VM tinkering with your wifi without your say so - there's been occasional problems like the latest hub firmware that sometimes renames the 5 GHz network so devices can't connect, or the "intelligent wifi" that seems to have caused issues for a minority of devices.
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