This needs to be highlighted more: the sales volume bias phenomenon. I've seen this happen on forums before, and will see it happen on forums again. Whatever people buy, they will have problems with. Some of those problems will be factory issues, some will be created by the user, and some will be entirely imagined. There are several biases which occur here. I have never, NEVER, seen any accurate data sampling on the relative defect rates of different airgun manufacturers. There is huge anecdotal evidence though that FX is currently doing really really well in the market and selling a LOT of guns, many of them to relatively inexperienced users. This would naturally lead to a lot of user generated reports on the forum with high google search ranking, which tends to be this forum. Contrast that with EdGun. A much smaller scale botique manufacturer, where the guns are hard to get, the reviews (particularly on high profile channels) are much more scarce, and at least stateside where there is only really one retailer and he doesn't have the full model/option range. What is that going to do to user generated reports of faults? It is going to suppress them, because there are going to be a lot fewer sales and what sales do occur are largely going to be to more experienced airgunners. This is going to result in a tiny fraction of the number of issues reported on this forum. Unfortunately that means there is absolutely nothing to create a useful dataset on this forum, and it also creates a confirmation bias: if you start thinking FX has problems, you're going to start seeing those problems everywhere. I've seen this happen before on other forums with other products, and I'm sure I'll see it again too.
To be clear I'm not saying whether FX has a higher defect rate or a lower defect rate than EDgun or Daystate or anyone else, I'm saying nobody here has provided any data to suggest anything one way or another. Given the absence of such data, and a very reasonable explanation for the flaws in user-reporting on a forum, I think it is irresponsible to "authoritatively inform" people of the "problems which plague FX guns." The plural of anecdote is not data, and we should keep that in mind.
You want an example of this weird untrue FX bias/rumor/malarkey flying around here? I see, time and again, the argument made that FXs only shoot JSB pellets. And this has been marched out into mantra now, where you can practically say it unchallenged. What? What kind of ridiculousness is that. I don't keep a lot of different pellets on hand, but I went out just this Sunday and shot a couple groups out of an FX Crown at 100 yards with JSB, Crossman Premier HP, and H&Ns. And you know what? They all shot well. <2MOA 10 shot groups on a day with a breeze, some drizzle, and casual shooting is pretty good in my book. So again, another myth to dispel about FX.
As far as what gun to go with, OP, to be honest I'd stick with the .25 for two reasons. 1) Any gun you have which is a shooter is a keeper. I realize some people get bored of guns and want to trade up, but I also tend to remember those people later expressing regrets. Never sell a shooter you love. It has been good to you, so keep your EdGun whether or not you want to go in on an FX later. 2) .30 was super hyped and sexed at one point, but things are starting to swing back around to the .25 and in some cases even .22. You're playing something of a balancing game of cross-sectional area for air to work on the pellet to generate power, and the same cross-sectional area for the wind to work against the pellet. As we're running higher pressures ever more efficiently, I see .30 (especially given how expensive it is, sheesh) fading out as people move toward heavier smaller diameter pellets for better ballistics relative to air consumption and properly big big bores for people who really need monster power for hunting larger or more dangerous game. There is plenty in this paragraph to disagree with, particularly my speculation on where the industry is going caliber-wise as god knows it is just my educated guess. But I hope you left with two nuggets of wisdom which are to be suspicious of forum mantra and never sell a gun which shoots great and you love.
My 2c.