I am happy to pay a good price if it means I can keep it for a while. I want something not too big...Buy the Garmin Edge 820, which was just announced two days ago, if you can wait until it is in the market, which will be in a few weeks. It is not too big. It has full features ready for fitness rides & extended touring.
If you cannot wait, buy the Edge 1000.
For other Garmin choices, read earlier discussion & somewhat outdated comparison chart.
Other devices that you see from other brands such as Wahoo Elemnt, Polar V650, & Magellan Cycle 505 are amazing products for fitness. They are not as suitable for extended touring rides.