Certainly better off in the garden. Roots like to be moist at all times. Best attached to a robust trellis cutting out the old wood in the late autumn and bringing the new pliable wood down to the horrizonal to encourage new flowering growth for the next spring.

We have dozens of roses in our garden, and I don't think it makes an awful lot of difference as to the type of soil they are in. Ours flourish in heavy clay-ey soil, and seem to benefit from a dressing of sulphur to keep blackspot at bay. I would always counsel growing in the ground rather than pots where possible.