I also use a trainer over winter, I live semi rural and it's just too dangerous on the roads round here for me to take the risk.
Last winter i did about 4x30mins per week and it helped a lot.
i had a Magnetic trainer and it felt "wrong". Just felt cheap
I got a fluid trainer, expect to pay almost £200, but it's is quite realistic and I change gear ever minute or so working up and down to vary the workout.
If you can afford £180+ go for fluid, way way better - different class of product altogether.
Oh, and be prepared to wear out rear tyres, or buy special ones for trainers, or really cheap ones just for the trainer.
Jeff