I'm not sure what the exact scan speed of the 5000 is, but at full resolution and 16 bits it is less than 30 seconds if ICE is off. The preview takes a little less than that. The official times are shorter than the practical times, because the scanner takes a little time to sort itself out after a slide has been inserted. I have three scanners in operation at once, out of the six I have, so I'm hardly ever waiting for a scan to finish.
I can't comment on the V because I have never used one.
I had big problems with the M1 film holders. Microtek are sending a replacement main holder, but it is on 12 weeks back order - maybe that means that they have had a lot of problems. The 12 weeks is up in early July for me, and I will be interested to see if the new holder is any better than the original one.
Mine does not hold the film frames tightly enough, so the slides vibrate ever so slightly during scanning. I found that the only way to get the best the scanner is capable of was to unmount the slides and tape the film to the glass film holder. The glass of that holder is between the lamp and the film rather than between the film and the sensor. My conclusion was that I was happy with the quality of scans from 8x10, but not from anything smaller.
Best,
Helen