Well if you like a naturally defensive vanguard then Hollow Ichigo is by far better. I do not like Stark because he isn't naturally defensive and requires to be doing a lot of damage for sustain, stark is generally for Senbonzakura users and slightly decent with Hyorinamaru but if you can stack he can be pretty good. Otherwise I would just recommend to stick with Hollowed Ichigo and if you are before level 100 then stick with Saijin until 110 unless you plan on getting a event partner VG.
Don't get starrk.
a year ago i would have said yes but now starrk isn't' up to it. not even the slightest, skill wise and utility wise he's bad. hollow ichigo deals more damage and his skill is much better. can be quite helpful in a lot of situations.