If I lived where we could go to a Christmas tree farm and cut our own tree, I would do that. I'd always choose that option.
However, if the choice is simply choosing one in a parking lot or some tree store set up in town where there's a construction trailer and we're walking on asphalt, well, that doesn't seem much different than choosing a fake tree in Hobby Lobby or another store.
The pros of a fake tree: you purchase it once, re-use it, you know how many lights it needs (or it comes pre-lit) and what tree topper fits it, there's no need to water it, no need to dispose of it in the landfill or mulch center.
The cons: it doesn't make your house smell like fir or balsam, only the most expensive trees look real.
Pros of a real tree: you can smell it - that scent is wonderful. Afterwards, you can take it to a place where they'll turn it into mulch and you often can get mulch in return for your donation. It feels a little more romantic and traditional than a fake tree.
Cons: the needles that fall off, the necessary watering, different trees may need different tree toppers or amounts of lights meaning extra expense every year, dragging it outside after a few weeks leaving a trail of needles that you'll still be vacuuming up from weird places in June, having to take it to the mulch place (meaning you have to tie it on your car again) or tossing it in the trash knowing that you've contributed to the landfill.
We moved to Hawaii this year and real trees are horrifically expensive (and plus they've been shipped a very long way and are already old by the time they arrive). The fake ones are also very expensive, due to shipping.
So we went to a nursery and purchased a live, very tall ti plant with large leaves (about 4 feet tall) in a pot. I covered the pot with Christmas wrapping paper, and we strung min lights all around the trunk and tucked more lights among the branches. It's a weird tree, but it works. After the holidays, we'll plant it outside.
So don't be afraid to to do something different this year. A fake tree vs real won't ruin the spirit of Christmas if you keep the traditions that are important to your family.