Griff, as mentioned difficult to compare due to two day meetings for 10th and single for most the 8th. I think Reevsey summed that up quite well.
Running costs I reckon are about the same with tyres + fuel.
As you know I don't exactly splash the new tyres around and I don't think you need to, but having a control tyre does make 10th more appealing.
Plus the 8th cars need more cleaning
Not really my cup of tea
But the track time for nitro is a major factor in why people race it - no doubt.
The deciding factor for me was that the 8th cars just don't feel precise/sharp enough for me compared to 10th, but that's probably my 12th heritage coming in...