Firstly you should do what is already done.
Users love consistency
If the majority of apps are doing it on the left top side, then go with that. It's very much like how a lot of phones, even though different companies, apply the same mechanics for touch screens (tap once to open an app, instead of twice, or even swiping at it).
Additionally, as research points out (thanks @Izahaki) the left side is better because it's much easier to stretch out, then to compress (less balance that way in the hand from what I found).
Also, I cannot express this enough: User test.
See what your target users (stakeholders) are more comfortable with or are used to. If they are tech savvy, I would go with consistency.
However, there is also something called learned behaviors. Something that users start doing after repetitive usage. So really, if you set a standard, don't break it and there could be a potential of learned behavior. However, I highly suggest you go with what is done first, then establish your own rules if necessary.