kf swears by them for SVJ. you're getting a double overload -- from the weight itself and from the height you're adding to jumps 2-n -- while still being able to produce force quickly. i wouldn't do them for high reps, moderate reps seems like the way to go.
if you do them be careful to use a weight you can REALLY handle and make sure you're keeping good form. i strained my low back/SI joint a while back doing DB jump squats, not even rhythmic ones.
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got home from work really late and i feel like garbage, bailing on the gym tonight. can't go tomorrow night either, guess i'll call it a one-week layoff.

ETA: did some kb work (swings and snatches), foam rolled, and did band work for shoulders. not much but better than sitting on my ass.