Unless you just like trying new stuff, no, it's not worth it. The OS is pretty cool, but coming from Android, you will become frustrated very quickly by the lack of apps and features. It's pretty obvious to non-fanboys that Microsoft has no idea what they're doing and will pull the plug on Windows Phone in the next few years. There's just no future in it. They've had 4 years to do something, and they only have 3% market share. They leave out obvious features, don't listen to feedback, and basically have an entitled attitude, expecting the thing to sell because "Microsoft." They're arrogant, delusional, and in denial.
If you want to try it out, your best bet is to buy a used Lumia 822 off eBay. It's a Verizon phone, but the SIM slot is unlocked. You can use it on Verizon, ATT, or Tmobile. All 3 have $45-50 unlimited prepaid plans. I've used my 822 on Straight Talk, Net10 (both ATT) and now Verizon. Everything works on all 3. If you go that route and need help setting up your APN's for GSM, hit me up. Everything works automatically with Verizon.