Surface quality on milled PCBs can be pretty good but you have to get a bit spendy. Also, the copper FR4 likes to delaminate under stress and deforms easily if

Surface quality on milled PCBs can be pretty good but you have to get a bit spendy. Also, the copper FR4 likes to delaminate under stress and deforms easily if you use the wrong cutting parameters so you typically want to go for a higher quality board material. It's pretty common for high end RF boards to be milled.