Do you trust yourself? I've always used a six part block and tackle (only 33# pull to take 200# aloft) and bosun's chair to get aloft whenever necessary and back in the days of wooden masts, to keep them varnished.Problem is there are few people I trust to hold the other end of the halyard nor do I trust those solo mast climbing setups they advertise. Sailboat rigger's gotta eat to, ya know.
In port, something like the Mast mate might be OK, but at sea one needs their legs to protect themselves (gripping or pushing away) when going up or down,or working aloft. Even with crew, the block and tackle is the preferred system at sea, so why have two? It isn't cheap to put together a safe, functional system, but it would last you a lifetime and be as safe a way to go aloft as there could be, if you trust yourself.