Apply Online: 

Entry to Dubai:

www.smart.gdrfad.gov.ae

Entry to other Emirates:

www.smartservices.ica.gov.ae

Visa Fee: 260 AED

Process Time: 1 to 2 business days

Personal Experience:

I usually fly to Dubai so I apply through GDRFAD and I never faced any issue with getting my visa issued. 

Once, I had a flight to Abu Dhabi so I applied through ICA but my visa request got rejected. I called ICA to ask for clarification and they said I had to contact the immigration in Abu Dhabi but they didn’t have a phone number to reach out. So the agent suggested to apply the visa from GDRFAD and then call Abu Dhabi airport to let them know that my entry port has been changed from Dubai to Abu Dhabi. 

I’d recommend to always use GDRFAD instead of ICA and then contact the port of entry for the change if you are not going to enter through Dubai.