I like the composted bark ones but there are plenty of growers who like those expanding 'peat pucks' sold at every hardware store at this time of year for starting seedlings.
If you use those, soak them to expand and don't forget to SQUEEZE out excess water before inserting your cuttings. Too wet= oxygen to the roots is blocked=cloning fails.
If you can find a higher humidity dome like at least 6", that's better. Air flow is important.
There is also a detailed cloning instruction linked in my signature. No pics, but some useful hints.