Honestly, they're all alright (at least I think so), but I prefer Suction Bomb Rush.
Burst Bomb Rush is probably great for dealing with enemies, but I wouldn't know since I never use anything with it (last time I did was level 2 when I tried out the Splattershot, then went back to Jr. and its Bubbler) so I can't say I prefer it most. Burst Bombs are alright by me though, they don't cost that much ink and they're decently powerful.
Splat Bomb Rush is probably the best Bomb Rush for inking large areas, since the bombs can roll after landing, but I don't like using Splat Bombs (they cost too much ink for me), so they're out as well.
Suction Bomb Rush is probably the weirdest of them, combining the Burst Bomb's exploding in the area it touches first and the Splat Bomb's delayed detonation as well as having a larger blast radius than both of those, but I like throwing them around to deny areas (or delay retreats, if the enemies go past them before they explode) and they don't cost as much ink as Splat Bombs (at least in my experience, could be wrong) so I prefer to use them in general more than Splat Bombs.
Really, for me, it came down to which one I like using more outside of the special, and that's Suction Bombs, so I like Suction Bomb Rush most.