I can't separate the two of them if i'm being honest as they're both very similar....as Somer says, the Plasmic Lights are cheaper so i'd stick with them. The Sky Bursts from Sainsbury's are pretty decent as well.
I have had both Deep space and Plasmic lights. They are most probably the exact same firework with just a different name and packaging as supermarkets like to have there own exclusive items. Would have to fire them both side by side to find out though.
If you can get them I would go for drone attack shot tubes.... only because they offer better VFM pack of 8 and you can get them cheaper than two packs of deep space. They provide more or less the same effect?