Ok it's been 2 years, but I just got a message from Google that I should download the Gmail app to my phone. I have been using the IOS default mail app all along. My only issue with the IOS app is that it no longer pushes email. I am curious what folks here think is better for Gmail, IOS or Gmail app, or perhaps something else? Online research for this is not definitive.
I briefly tried the Gmail app a few years ago but ended up switching back to the standard iOS mail app. The main reason for me is that, at least at the time, there was no way to change your default mail app in iOS. This meant that if I clicked on an email address from my contacts, calendar, or pretty much anywhere else the standard iOS mail app would open instead of the Gmail app.
The Gmail app also included ads while the standard iOS mail app did not. There might be benefits to using the Gmail app or one of the premium email apps available in the app store but the standard iOS mail app is plenty for my needs. It works well for what I use it for and I haven't found a good reason to look for another app.
I'm not a power user of email on my phone. I regularly read email on it and send quick replies for both my work and personal email accounts. If I have to type out anything important or long winded I will be moving over to my PC to use Outlook (work email) or Gmail web interface (personal email) almost every time.