Hi. Welcome to FlyerTalk.

Since you will be flying out of Newark, I would probably switch over to CO. However, not sure how well you will do on upgrades from EWR-LAS, even as an eventual Plat on CO. Perhaps some others can post their success rates. The only thing you would really gain, aside from maybe a few extra Plat bonus miles, would be upgrades. If you aren't able to get that benefit on the routes you take, I might just stay with Delta. You get all the other benefits if you stayed with Delta.

Like I said, I would probably do it, but it is something to think about. Is your move to NJ permanent or only temporary? If only here for a little while, might make sense just to stick with Delta.