Recommendations for new, lightweight vacuum please

Well, I had a lovely surprise yesterday. I had emailed my SIL as I knew he would have done research as to which one to buy, and they have come back and said they will buy us one. How kind they are, and we look forward to when it arrives.

Thanks all for the recommendations. I love my Gtech and wouldn't be without it, but I am thinking of going down the robot route, if I can make up my mind which one to choose.
Our daughter has one, and it just trundles around upstairs, doing it's thing. I like the fact that it can go underneath the bed etc. So I will be looking and researching when I have nothing else to do ?

Another vote for the Shark cordless. Very light and easy to use or carry.

Bosch cordless. It was the only one that was light enough for me to use. It's brilliant. I can vac the bungalow 4 times before recharging. Got it in pc world's sale for £127 saved £170 .

I have a Shark and its been great ,my last one was a very heavy Bissell specifically for pet hair .The Shark does just as good a job with my long haired cats cast hair

I love my robot vac. It cleans thoroughly with little effort on my part. Mine is a EUFY and I bought it from Amazon.
It has several programmes and can be used on a timer and it goes back to it's charger when the battery runs low.
You will need to make sure that there are no wires, shoelaces etc. for it to get caught on and it isn't clever enough to empty itself.