Need your advice on iPhone/data setup

A big life change means I'm looking at alternatives to speeding $100+ monthly on a new iPhone contract (and likely a new phone, too...)

I had a company phone until I recently left my job. I kept my number by porting it to Google Voice, and I'll keep my phone (Verizon 4S). I've kept my texting/calling going by using a combo of the Google Voice and the Talkatone VOIP apps. So far so good.

Here's where you come in...

• Would it be crazy to get an iPad w/ LTE, and use this as a hotspot for calls when I'm not already on wifi (rare)? (I don't have an iPad, but I've considered it for a while.)

• 
  Would it make more sense (data economy/cost or portability) to just get a MiFi?

• Or would it be frustrating after having a full-blown iPhone (using about 800MB/mo.)? Should just pony up for a new contract?

Thanks!