CFDs are definitely more risky, greater reward potential but losses can exceed your initial deposit.
Holding shares you can ride out a downturn but CFDs you either cut your losses or add more deposit. CFDs aren't affected by market depth though but you need to be aware of spread.
I've used IG and their platform and costs are very good, important to keep your margin low rather than near your maximum. Eg they offer 4:1 leverage on some stocks but safer to use 2:1 or 3:1 to give yourself a buffer.
