Ah ok, I can do that no probs at all but you'll have to just take my word for the results as I don't have any recording gear to make a decent video of the outcome.
Terry01 , we don't need proofs , user observations and feeling is enough .
I spent 45 mins or so there with my 121GW and U1273a just measuring lots of different things between the two meters. I used 2 sets of the same leads in both meters depending what I was measuring. So the test was as fair as I could make it leads wise.
First off before I say anything when I first got the 121GW with firmware v1.54 installed I tested a load of resistors, caps, diodes and anything else I had laying around and I thought it wasn't that bad.
Today with it side by side with another meter it was awful! Very slow in everything apart from DC volts where it was ok or as good as the U1273a and it also jumps around quite a bit.
When measuring resistance it always jumps to between 20-40k and then settles on a more realistic number where the U1273a just lands on the measure and stays there solid.
On AC volts it's a wee bit slower than the U1273a but settles fine after a couple seconds.
I also measured the A ranges with a couple 9v batteries, 1 has been used a little and 1 is quite quite badly depleted which was very strange.
I used a 3.9 ohm power resistor as a load. Both meters showed around 87mA on the A range when measuring the newer battery but when i then changed range to mA range the 121GW would not read it and kept showing OFL where the U1273a measured it no problems in either A or mA. I found that very strange! The dud battery measured 200-300 uA or there abouts and both meters measured this no problems in the mA range.
When i tested the 121GW on it's own when i first got it it really didn't seem that bad, maybe my inexperience played a part in thinking that too though.
A couple things to sum up... the U1273a is around £100+ more expensive and has had time to iron out all the teething problems etc and also Keysight has much more experience and has made loads of previous other meters to gain knowledge from along the way. I think the 121GW will catch up in time but we'll just have to wait and see. I still use the 121GW at my bench just because i like the meter and a couple seconds extra to wait here and there doesn't matter to me.
I can see where it would matter to someone who needs quick measures dead on every time though. It's funny how a couple seconds extra makes the 121GW seem painfully slow beside the Keysight!