hmm, you definitely have a hard decision to make here.
I checked out your channel and your video quality looks decent but If you want to upgrade I can't tell you which camera to buy because I don't know your full story but I can give you some things you need to consider.
Firstly, how much of an improvement are you hoping for? You can go with a cheaper camera but you might end up not being happy with the extent of the upgrade.
It's best to go on YT and look at the footage shot with those camera's, make sure they use the kit lens for best result. Then you can see if your satisfied with the cheaper options or if you want to save up more for a better camera.
Secondly, how serious are you about YouTube and how much are you willing to spend in the long term?
If it's more of a hobby, there's no point spending stacks of money on equipment (unless you can afford it). If you're thinking of turning this into a job one day, than investing into decent gear early might be beneficial.
Thirdly, the thing about DSLR's is that it's more important what lens you have rather than what camera.
I can suggest a video called "Pro DSLR + Cheapo Lens vs "Cheapo" DSLR + Pro Lens" by DigitalRev TV. It's more about photography but still applies to video.
If you decided to go with one of the more expensive options like the 70D you will go over your budget and still might end up spending even more on a decent lens to get the most out of your camera.
Another thing to consider if you go with a DSLR is if you buy body only or with the kit lens. I don't know about other brands but Canon's new kit lenses are decent BUT they were made for photography rather than video. If you're serious about camera gear, sooner or later you will end up getting a different lens because the kit lens is definitely limiting the performance of any decent camera but once again, watch some videos to see if you're happy with the quality.
BUT, if you buy a camera with the kit lens you save a bit of money because it costs less than buying it separately.
Even if you go with the cheapest DSLR on you list and get it without the kit lens you will still end up over the $600 budget so I have another suggestion for you. I think that the Canon t3i or the t4i together with a decent lens, you might still go a bit over budget but it will be less than with the cameras on your list. I know that those 2 models are fairly old but if you know what you're doing you can make their footage look great.
Check out a channel called DSLRGuide. It's run by a very cool, young film maker who uses the t3i. His videos look great because he took the time to learn how to use it. With a bit of research you will be able to find the lens he uses, all I can remember is that it's a Tamron.
Now when it comes to P&S's the G7x is a great choice and might be a great compromise for you. DSLR quality in the tiny body will be great for both vlogging and studio work.
Lastly, think if you really need this upgrade, as I said, your video quality is decent and it didn't stop you from getting 1400 subscribers. It might be smart to wait longer, learn more about camera equipment, save up some more money and then upgrade.
Learn from my mistakes, I rushed my camera gear purchase and now I slightly regret some of my purchases.
For example, when buying audio for my setup I watched some comparison videos and decided to buy the Zoom H1 to record audio. It's a audio recorder with a microphone built in but it's not an actual microphone that you can connect to your camera. I already spent all the money in my budget on other things so when I've done some more research and realised it wasn't the best idea a month later I could only afford to but the Rode Video Mic to connect to the recorder. For the price of those two I could have got the Rode Video Mic Pro which works as well as the recorder connected to microphone but can be connected straight in the camera. (no need to sync audio)
In September I was in a similar situation as you, I had a tight budget and a lot of choices to make, I will share what I decided to do in case you find it helpful.
So, I had a budget of £1000, I wanted to use it to buy as much equipment as possible so I spent days researching different options.
I was choosing between the t6s and the 70D, there's £100 difference between them. I didn't have the money for a good leans so I decided to get a camera with the kit lens. I didn't want to be stuck with just the kit lens so I decided to get the cheaper camera and I got a 24mm Prime lens for roughly £100 to cover the difference between the 2 cameras.
The camera, kit lens and prime lens were roughly £660, for the rest of the money I got the recorder and mic mentioned earlier, headphones, extra battery, back pack, reflectors, SD cards and a camera cleaning kit.
The T6s is a very good camera, and I'm happy with it but now few moths later I wish I spent the extra £100 on the 70D. This is why it's important not to rush purchases
Ok, I hope this was helpful, it took me a while to write down all of this
Good luck with your purchase
