As a budget brand-name 34-inch ultrawide gaming monitor, the Gigabyte GS34WQC checks all the boxes. It offers good picture quality without hardware calibration, it feels very responsive in terms of input lag, and you can adjust its height, which is about as much as you can hope for when it comes to ultrawide monitors. One could argue that the 120 Hz refresh rate doesn't impress, but that's where the factory overclocking feature kicks in, which pushes it to 135 Hz, without any noticeable side effects. At that point the experience is almost identical to gaming on a 144 Hz monitor.
However, with this being a 34-inch ultrawide panel, the Gigabyte GS34WQC can be utilized for much more than just gaming. Any kind of productivity work, particularly that containing timelines (think video and audio editing), feels excellent. With that in mind, this is just as good of a choice for predominantly desktop usage, especially if you're on a budget. Sure, Gigabyte cut some corners to achieve the $300 price mark; you're not getting a USB-C input, a KVM switch, or even a basic USB hub. However, what you are getting is a capable ultrawide panel, that in no way feels like a victim of budget constraints. For many, that will be a completely acceptable compromise.
You should be aware that there are multiple other 34-inch ultrawide options around the $300 price tag, such as the ViewSonic Omni VX3418-2KPC, AOC CU34G2XP, Iiyama G-Master GCB3480WQSU-B1, LG 34WP65CP-B and Acer Nitro XZ342CUV3. They fall within $30 of the Gigabyte GS34WQC and offer higher refresh rates (144, 160 or 180 Hz, depending on the exact model), but as I have yet to test any of them, I can't comment on their picture quality. With that in mind, if you're after a proven brand-name budget ultrawide option, the Gigabyte GS34WQC is a safe choice.