You shouldn't get hot oil by the time you've drained the sump . Equally you should only get a few drips if you have waited for the sump to empty.
Cobblers
The spin on is easier to remove
Cobblers
The spin on is less likely to leak,
Cobblers
I've never had a spin on leak and my last cartridge leaked when done by National Disgrace. The spin on is much less likely to be over tightened and jam.
No part is infallible from retards incorrectly fitting it
The spin on is around half the price of the cartridge.
About 2/3rds, agree it is cheaper
The spin on is much less messy, just chuck the old one, no messing with replacing the paper.
The paper element is definately less messy to replace
I suspect the spin on is a more effective filter. You cannot crush the paper when fitting a spin on unlike a cartridge.
I would actually say that I think the paper element type is more effective than the spin on. Not quite sure how you can crush the paper element. But at least you can check the integrity of it before fitting.
Apart from that the cartridge is great.
I'm not fussed which is fitted. Both my Omegas have one of each. I have a slight preference to the paper element type, due to slightly less messy change, and the fact it doesn't soak the crank sensor in hot oil. But its not enough of an advantage to change the spin-on type - having them all the same is a stronger argument.
The Spin-on does have the advantage of being able to write on it the mileage and date of change (which caught out those lying retard bastards at Evans Halshaw in Milton Keynes

)