Hi blilith and welcome!
There are a number of emulators available today for the QL with the key differentiators being commercial vs.no-cost and, most significantly, how closely they emulate an original QL OS vs. the later SMSQ/E OS.
You have probably already found them referenced/available on the Sinclair QL Homepage, hosted by Dilwyn:
http://www.dilwyn.me.uk/
My own (personal) assessment, having played with a few of the emulators would be:
Q-Emulator - still commercial - very capable and quite fast - high compatibility with original QL OS and, with extension, a version of SMSQ/E - has an SD-Card image driver available and some neat software deployment options - available for Windows and MacOS
QPC2 - made free-ware after originally being commercial - probably the most capable and fastest SMSQ/E emulator available today, but quite far-removed from the original QL - available for Windows only (but known to work fairly well under WINE on *Nix) - my emulator of choice - just to be transparent!
SMSQEmulator - free-ware - capable but less swift emulation of SMSQ/E specifically - very convenient JAVA implementation which opens-up the platform options
uQLX - free-ware - using a similar emulation engine as QEmulator, a bit sticky to get running first-time but very capable emulation of original QL OSes with some Unix like extensions - available for *Nix (now including ARM processors, which is pretty unique)
QLAY/W/2/2k - free-ware/postcard-ware - moderate capabilities based around the original QL OSes only - very lightweight and runs on DOS/Windows (/W) and *Nix - QLAY was my first foray in to QL emulation as an adult after my first affair with the original QL as a teenager!
They are all a work-of-art in their own right and, at one time or another, I have needed to turn to one or the other emulator to achieve what I wanted to do in the easiest way.
I particularly used Q-Emaulator, for instance, to help with moving files on-off my QL formatted SD-Card to transfer files between my QXL emulated filesystem and a real QL with SD-Card reader. My software development was typically carried out on QPC2, but then tested a bit in QEmulator to get a better idea how it would function on the target QL.
You'll hear a number of absolutely valid, yet quite diverse opinions on the Forum - the above is only one such opinion - but might help you decide on your emulation approach.
Good luck!