How big is your home? What is your budget? Who is your ISP? What is your internet speed? What router are you currently using? What are you expecting from getting a mesh system?

Basically all these questions + more come into it. You can't really say if a system is good without understanding how the system is going to be used.

legup: Average size 3 bedroom house. Fibre connection. Currently speeds on wifi under 50Mbps even though line speed is 900. Vodafone ultra hub

are you only getting 50Mbps when you are next to the router? - i would be contacting vodafone and trying to diagnose the problem, as you may find buying a mesh unit you will be flushing money down the toilet as you still will only get 50Mbps.

with this said, if it has a ethernet plug, then spend the money to get it cabled.. mesh units in my view are ONLY better for coverage and speeds are still crap.

50 Mbps is a 2.4 GHz connection.

Spyware:

 

50 Mbps is a 2.4 GHz connection.

 

Good point, maybe the OP should perform a factory reset of the Ultra Hub?

Not a networking expert, but having just upgraded myself (VF Deco X20's) I think the ones you linked are old technology, and you should spend a little more money to get something with more channels and WiFi6. 

It will undoubtedly improve your WiFi coverage but probably not the speed.   Definitely something wrong if you are only getting 50Mbps from the UltraHub!  I have had 2 of these fail when they 'lost' the 5 Ghz channel. Perhaps your has done the same?  VF just sent me a replacement.      

If you are staying with VF, why not take up their deal to get the X20's free?  You just have to sign up for a certain term.   

legup: So is the Vodafone wall to wall Wi-Fi better than this product?

Ethernet line testing gives 900Mbps from memory - the slow Wi-Fi speed is due to loss of signal which rapidly diminishes with distance I think but I should further diagnose this.

I only became interested in this TP link due to the especially price.

So are you connected to 5 GHz or what???

"Ethernet line testing gives 900Mbps from memory "

some PCs/laptops/tablets will only do 2.4Ghz
If thats the issue , a Mesh system will be a waste of $  

Go into the router , give the 5.8Ghz wifi a differnet SSID (wifi name) and manually try and connect to that 5.8Ghz wifi

"the slow Wi-Fi speed is due to loss of signal which rapidly diminishes with distance I think but I should further diagnose this"
Ah yes, diag the issue is ALLWAYS the first step .  :-)
Retest in the same room as the router

Those models are decent and will work well. Have a pair of the next model down for parents house and works very well, easily delivers there 100mbp connection through the house. Those ones should top out around 300-400mbps for wifi on 5Ghz.

There are newer models available but for ~$170 for 2x that's a very good deal and those will work well for years, and your unlikely to have much wifi6 stuff yet anyway.