I see these threads a lot, and there are several questions to ask before you buy ANY transmitter:
1) What do you want to fly? Quadcopters, Helicopters, gliders, warbirds that have retractable landing gear and bomb drop capabilities?
2) What features are you looking for?
3) Do you want to fly bind n' fly planes like the ones from Horizon Hobby, or are you willing to swap out the pre-installed receivers for a compatible receiver to a different radio?
4) Do you know how to get help for the transmitter you're looking to purchase? Are there other people at your field flying with it that can help you set it up if you need help configuring your transmitter?
5) How much are you willing to spend? And this question should NOT be the primary question to ask, because if it's all about cost, you're going to find cheap transmitters that will do the job for right now, but you'll end up spending quite a bit more in the long run.
For example - Let's say you want to fly gliders. Seems simple, right? At the start, you can get away with a 2 channel radio controlling rudder, and elevator. Then you hike up a hill, and throw it off, where you then fly it until you run out of updraft/thermal currents. But what if you can't find any thermals or updrafts? So you put a motor on it to get it up in the air. Well, that requires throttle to get it up, so now you're at 3 channels. Or you decide you want to have it towed up into the air, so you need a servo that can release the tow hook when you've reached sufficient altitude, right? That's another channel. So you learn to fly with that for a little bit, but you decide that you want more of a challenge with gliders, so you get one that adds ailerons. That's another channel. And then you add on flaps - yet another channel for the separate flaps for that, because they work independently of the ailerons.
It all stacks, and that's just for one type of plane. Now, that's not to say that you can't fly with a cheaper radio, but if you buy the cheaper radio and decide to move up, you now have to give up the radio you WERE using because it doesn't have the capability to support the multiple channels, or mixing, or computerized setup that the more expensive radios have. It's a "Buy once, save later" mentality.
Features are something else to consider. Do you want a radio that speaks to you and tells you how much time you have left on a charge, i.e., "30 Seconds remaining", or do you just want a generic beep as a warning? Do you want telemetry capabilities that read off of sensors installed in your plane that tell you how high/fast/far away your vehicle is? Do you want the capability to do mixing, so you can utilize differential thrust and allow twin engine motors to turn the plane as opposed to rudders? Not all transmitters have these features.
With regards to the bind n' fly question - there are multiple protocols out there for planes. Think of this as an "Android vs. Apple", "Ford vs. Chevy", "Playstation vs. Xbox" type of situation. Each brand/protocol has its pros and cons; each one has its followers. Personally, I like the DSMX protocol, which is the protocol that is used by Spektrum radios. But, there are others, like FASST, or FrSky, that operate on a different protocol. If you choose to go with something other than DSMX, and you want to go to the hobby shop and buy one of those bind n' fly planes that are already built and nearly ready to go out of the box, you'll need to swap out the receiver for a compatible receiver - which means added cost. Where some people have an issue with it is that buying a Spektrum branded receiver, you'll pay more for it vs some of the other brands. There are cheaper alternative brands that use DSMX, such as OrangeRX and Lemon, but many hobby shops don't stock them. You might run into that same issue with some of the other brands, such as the Futaba or FrSky brands - it simply may not be stocked locally, prompting you to buy them from an online retailer, which has its own pros and cons.
That also ties into assistance. If you are part of a club that has a bunch of people flying Spektrum radios, they'll most likely be able to help you set it up to fly properly. But try to ask that same group of people how to set up an FrSky radio, and it's quite possible you'll get blank stares, leaving you to figure it out on your own - which stinks if you're at the field and away from a computer or internet signal to get online help from.
I see
@kdobson83 mentioned the DX8e, which is a SOLID radio, and what I'd recommend for most pilots who want to get into the hobby and expand up a little from the basics; It's theoretically possible you might need more than 8 channels, but 90% of the people out there flying in the hobby don't, unless you're doing the high end gliders, or warbirds with bomb drops and retracts, etc...The Spektrum brand is one of the easier radios to set up, it's a solid work horse, and it's compatible with all of the bind n' fly planes, but they're a little more expensive than other brands.
Ultimately, it comes down to the questions I asked above, and what you think is going to be best for YOU based on how you answer. The FlySky i6 or the Jumper radios might do what you need initially, but they may not last as long or have as much functionality as say, the Taranis X9D or the Spektrum DX8. It's really up to your needs and where you're planning to go with the hobby, where you ultimately want to end up, and whether you want to invest now, or spend a little now and then buy the gear you want for what you want to do later.