I love my Garmin Mk2i, but despite my bias, I think Teric is the better choice if you won't use the non-diving features. Garmin is expensive!
However, the following factors might make Garmin a better choice for you even if you won't use any features besides the dive computer:
1. You want to use the GPS to navigate to dive sites.
2. You want to use the advanced subwave dive network capabilities:
- View tank pressure for up to 8 paired Descent T2 transmitters (if you're only using one transmitter on your kit you can monitor 7 buddies' gas)
- View diver depth
- View public tank name
- View diver distance
- Receive messages
Even if you don't think you will use the Mk2i as your daily smart watch, read up on its capabilities before you decide. It is a lot more than a smart watch / dive computer combo. The dive computer is layered over a Fenix 6X Pro, so google that computer to see everything the Mk2i does besides diving. Beware: Garmin has started playing the subscription game, so if you find a feature that you think you will use a lot double check that your use case won't require a subscription (or confirm that you'd be willing to accept the added cost of a subscription).