I have done LoB and SJ on two different occasions and they visited more or less similar sites(log book to prove). The only difference is the number of dive offered. 3 vs 4-5.Actually really considering SJ now! Reading up about it, the location and ease of access seems wonderful (not to mention money saving). Same with not having to deal with the potential seasickness of a newer diver on a LoB. Would the dive sites we'd access be limited, or is it drastically inferior to a LoB in terms of what we'd see, @Centrals ?
However, if seasickness is a real concern then none of them is really suitable. Because we are talking minimum of 5-6 hrs travelling on the boat(not counting time underwater).
SJK is highly recommended.