Welcome to iMore!
What are you currently using for a phone? Both great choices for a phone in the 6s or SE. SE will leave you with some money in your pocket, yet still has virtually everything the 6s does. The SE targets the crowd that wants a smaller phone in their hand. I personally own the 6 and have got use to the larger size. Either is a great phone and will last you for many years to come.
Please feel free to ask any questions you may have. Many knowledgeable people on the forums that can help you. Once you move over, let us know which phone you went with. I have been using iOS since it was introduced and have come to find it a large part of my work flow. Hopefully you will find it just works as I have.