BlackBay,
Longish post, but here are some basics:
For mastering onto analog, you would, realistically, want: a 1/4-inch tape machine (that's the width of the tape you will be working with, and you seem to be looking at such machines, so that's fine.)
The machine should have the following:
2 tracks only. This means you record the entire width of the tape in one direction only, on 2 tracks, which is stereo. This gives you the highest quality for your purposes. For that reason, forget the 3440. It has 4 tracks which you don't need, and because there are 4, you get lesser quality.
The machine should record at 15 inches per second for optimum sound. You can find slower (and occationally faster), but 15 is for your quality purposes 'the speed'.
With 15 Inches per second in mind, the machine should also be able to take 10.5-inch diameter reels (the 'big reels'.) At 15 Ips, you will get 30mins or so on a 10.5inch reel.
DO NOT trade longer recording time (i.e. slower maximum speed) for lesser quality. 30mins per reel may not seem like a lot, but you get what you pay for. 30mins is plenty to master several songs. If you want, you can always re-use.
A note on tape: DO NOT buy used tape on FleaBay. You have no idea of what you will wind up with.
There is a whole slew of older Ampex-brand tapes that have severe problems (called Sticky-Shed) which basically render them useless, and can absolutely gum up your machine in the process.
There is good new tape stock to be had, so no need to mess with those.
Machines (you ask the seller if they are 2-track and 15ips if it doesn't say, because some come in many variations.)
Here are some common 2-track models that would serve your purpose:
Tascam 32. There is a higher-grade machine called the BR-20; depends on the pricing on EBay.
Otari 5050, preferably Mark 3 or higher (the model should indicate which it is.)
Revox B77. It may be tough to find affordably in the 2-track, 15ips version, but I wanted just to mention it since it is out there.
Also, don't forget the home machines.
Under "Reel to Reel Machines" on EBay you will also find older consumer machines from the mid-70es that sometimes feature 2 tracks, 15ips, and take big reels.
Teac, Sony and Pioneer are some examples.
In all cases, shop carefully. You will be dealing with an aging, mechanical device. Make sure the seller has maintained it and that you won't have to buy (especially) new rubber rollers or belts as soon as you get the machine.
Ask questions. If need be, ask here what to ask.
There is more to add, but that's good start. I am sure you will have more things you want to know, and if you make the jump, you will want some pointers on maintenance and such.
Feel free to show us a listing if you find a machine that seems appropriate.
Good luck with it all,
Best,
C.