Maybe it' just personal preference, but for me the shift/ctrl/alt + number/letter combinations for attaching, removing and dropping equipment feel a little bit unnatural (using keyboard mode).
When I'm thinking "ok, let's remove component D and attach component 4 instead", I would rather press r, d, a, 4, instead of alt+d, ctrl+4. The two reasons for this are:
1. because I find it much harder to memorize something like "alt = remove, ctrl = attach" than "r = remove, a = attach" and
2. because some combinations (e.g. ctrl+I) are only possible using both hands and I don't want to take my right hand off the numpad