quite a bit different. far less poppy, without the JP guitar hooks and crescendos and the like. still subtly catchy, and lyrically similar, at least in terms of themes. overall much more mellow. the last.fm label gives a reasonable indication of the difference (and i'm sure you can imagine the continuity/similarities). E For Explosion: indie, shoegaze, atmospheric, emo, dream pop.
if you liked JP, but also like more muted stuff, then i think you'll love EfE. reinventing the heartbeat had some fantastic songs. highly recommended.