Well some quick tests... I set up power supply to run through 3 voltages. They were 1.263V, 17.632V, and 23.928V.
The keysight read 1.2624V, 17.630V, and 23.928V. The 870 read 1.2623V, 17.633V, and 23.93V.
So that seems alright. I also set it to switch between them every second. The keysight I could see the voltages every time. The 870 I could see 17, and 23 but it never had time to range for 1V.
A 0.68 ohm resistor read .69/.70 on keysight and 0.73 on 870.
A 2.2 ohm resistor read 2.22 on keysight and read 2.27 on 870.
No rel to account for leads but for everything I used the same leads just swapping input jacks so apples to apples. The resistance kept going down on the 870 but I stopped at 5 seconds because that's about the maximum patience I'd usually have. The keysight was a second or less to stable. Both resistors were 5W 1% tolerance and 50ppm stability.
47nF capacitor: Keysight was 48.30nF, 870 was 46.10nF. 47uF: Keysight was 49.21uF, 870 was 49.22uF and pretty slow to figure it out. The capacitors were 50V 10% tolerance.
So it seems alright in accuracy but definitely slower than the keysight, surprise. The real problems for me are that 1 of 2 arrived with what appears to be a short under the blob over die(This could have been from sticking it in a mains outlet just to see if it'd blow up, but it didn't seem to have a problem reading it). The leads are not very good and don't seem to make good contact, the extra leads it came with would be better but then you've got longer leads and screw connections at both ends. The multimeter specific leads in general were probably trash. I couldn't even verify they used pvc for the insulator because they said nothing. I think the manual warnings of 36vdc and 24vac as limits is a good indication not to mess around and at least get some decent leads (and avoid mains).