Does Clowney have DE eligibility in your league? JPP seems washed up as a quality IDP option. Jackson probably had his career year last year. But i'm not sold on Lee but he was highly thought of in dynasty circles before last year. If you are going for this year I would go with Jackson and hope he's a decent WR3 for you with some upside with RG3. If you are dynasty I would go with Lee/Clowney.
This year only I'd rather have DJAX and JPP. JPP is still young, he may have just had some problems due to scheme or nagging injuries. . Might bounce back. Clowney could be the next big thing, could be the next big bust. If it were dynasty I'd go with the young guys because what your giving up isn't a lot. But for just this year, I think the vets have it on this one
Plus it would be nice to have the DJax-RG3 TD combo! And I would think Clowney's upside is JPP, no? One bad year, I'm not ready to turf him, he's a freak as well!
If this is for your dynasty league, take Clowney. I'm not a big fan of Lee though. Terrible Jags team. And next year Lee may be behind Blackmon as well.
JPP has trouble staying on the field because of health. And I feel DJax may have trouble staying on the field because of his attitude. I look at him as a guy who happened to stumble into a 1300 yard season.