Noob alert.

So is it infact true that trainers are bad for the frame? And how much of a work out can you really get with trainers? Is the resistance level high enough to simulate heavy climbs or do you use sprints to keep the HR up for intervals?

Trying to see if I could sell off my Spinner and replace it with a trainer and a bike, or keep both. I like the Spinner because the resistance level can get Mnt Everest if I wanted.