There are a few considerations to make when choosing the shape of carabiner on the ends of your quickdraw. Firstly, whether or not it’s a keylock. A keylock carabiner, like the one on the Black Diamond Livewire, will be slightly more expensive but has the advantage of being significantly less likely to get caught or stuck on anything.
Secondly, the material. With modern forging techniques, it’s possible to have extremely light carabiners. These light carabiners are typically just as strong as their heavier counterparts, but they do tend to wear down from rope-rub a bit quicker.
Both solid? One solid one wire? Both wire?
In Australia, with its long history of carrot bolting, a combo of one solid gate and one wire gate, as found on the Black Diamond Posiwire, is common. This is because wire gates are lighter and easier to clip, making them the preference for many climbers, but they’re too thin to safely use with carrots and bolt hangers. As old routes get rebolted with modern techniques, this is becoming less of an issue.
In other areas of the world, double wire-gated draws are already quite common. The big advantage of wire gates is that they are lighter, reducing the chance they will will vibrate open during a fall (which can temporarily - but dramatically - decrease the strength of the carabiner).
The other consideration is how wide the gate actually opens - a wide gate opening allows you to easily clip the rope without risking your finger getting jammed up inside the carabiner.
The dogbone is the name given to the sling that connects the upper and lower carabiners. The primary considerations are length and stiffness. For length, it’s a good idea to have a collection of various lengths. This way, you'll always be able to choose the correct length draw to avoid unnecessary abrasion and force, as well as minimise rope drag.
The thickness of a dogbone affects its handling, with a thicker dogbone, like on the Black Diamond Livewire, being easier to handle and clip. However, the flip side of that is less mobility of the draw leads to more rope drag in wandering routes. A thick dogbone is also easier to grab if you’re pumped out and feeling sketchy and absolutely have to clip - even if it does ruin the send attempt.
How many draws you buy depends on the area you’re climbing in. Around South-East Queensland, 10-12 draws will get you up the majority of routes, but if you venture further afield you may run into longer routes. The best thing to do is check with local climbers and guidebooks as to how many draws are recommended for the area you want to climb in.
There you have it! These are the primary factors to consider when buying new quickdraws - hopefully you'll be able to pick the ones that are right for you!