>A tip I read is the guillotine ones tend to slice and cut while the scissors type compress the nail to a flat plane before they can cut and it's suspected the compression part is what a lot of dogs object to. I do use scissors ones with no problem.
It's actually the other way round. Because the guillotine only cut from the top down onto a flat edge it's those that compress the nail. The double bladed scissor type are the ones that compress the least because they are cutting equally from both sides.
Make sure your blades are sharp. I have 5 dogs I do on a regular basis. I use the Miller's Forge brand scissor style (you can find them on Amazon or at dog shows) to cut the tips off, then use a cordless dremel to get them back as far as I can beyond this. This way there is less chance of cutting into the quick (though I do still nip it from time to time), and the closer you get to the quick with the dremel it will start to recede and you can even get terribly long nails shorter over time.
If you do quick the nail the best thing I've found to stop it is actually super glue. Anything else and it can open back up or takes forever to close. I always put it on a cotton bud first. If you put it directly on the nail then overflows can end up with sticking two toes together (OOPS), so small bit on cotton bud then touch to the toenail and 'flatten' with the dry end. Super glue is the same thing as liquid skin, so perfectly safe.
This is the best dremel tutorial I've seen, and it's how I taught myself (though the whippet toenails aren't as short as her dobies).
http://www.doberdawn.com/doberdawn/dremel.htmlI had one girl who was terrified of the dremel, so we desensitised her to it over a few months with yummy cheese treats and a clicker. After that, that's how we trained all the pups to accept it. None of them like toenail time, but they accept it.