● Price: Quickdraws range from about $10 to $25 each. Why such a range? The more intricately a carabiner is shaped, the more expensive it becomes. A pricier hot-forged carabiner can be sculpted to give it strength where it needs it and shave weight where it doesn't. Dyneema sling material, as opposed to nylon, also jumps the price up. It is lighter, stronger and less bulky.
● Weight: Quickdraws range from around 60 to 110 grams. Weight is important and adds up because you may be carrying many quickdraws. Lower weight gives you an advantage in sport climbs or fast-and-light alpine climbs. On the downside, you usually end up with small carabiners that are harder to clip, especially if you have big hands, and a sling that is not as durable.
● Carabiner strength:
An important point of comparison, strength varies from one quickdraw to another. It is rated in 3 directions: lengthwise (major axis), sideways (minor axis) and while open (major axis open or "gate open"). While all climbing carabiners pass UIAA and CE standards, carabiners do break from time to time. It is up to you to weigh the relative importance of carabiner strength. Gate-open strength and minor-axis strength are where you see the most variation. Generally, smaller and lighter carabiners are weaker, though this is not always the case. See below for why do carabiners break?
● Sling strength:
This is a minimum of 22 kN whether you choose nylon, Dyneema or Spectra (see details under sling materials
● Size and shape: The smaller the 'biner', the more difficult it can be to manipulate (i.e., unclipping the quickdraw from your harness clip and clipping the bolt or rope.) Carabiner shape affects ease of use as well, especially if you have large hands. Ideally, go to your local REI or other climbing shop to hold the carabiners and get a feel for how they will work with your hands.
● Gate open clearance: This refers to the width that the gate can open, plus the depth and shape of the bottom of the carabiner below the gate. Generally the smaller the carabiner, the less clearance it offers. Too little gate-open clearance may lead to your finger getting stuck between the gate and the carabiner body while clipping; too deep a clearance is just harder to clip. An ideal amount makes clipping the rope into the 'biner' much easier. Again, go to your local climbing shop and see what works for you.
● Wire gate vs. bent gate:
Traditionally, the bottom, or rope-clipping half of a quickdraw, is a bent-gate carabiner. This allows for easy clipping. Wire-gate carabiners are slowly replacing the bent-gates because of their added safety in that they reduce the likelihood of "whiplash" and carabiner failure. (Some wire-gate carabiners have a subtle bend in the gate to aid in rope clipping. These are possibly the best of both worlds.) Neither carabiner is foolproof, but you can minimize this risk with careful use. See below for why do carabiners break?
● Wire gate vs. keylock: A keylock carabiner has a smooth notch where the nose of the carabiner and the gate interact. This keeps the carabiner from hooking and catching onto your harness gear loop, bolt hangers and other slings, any of which can be quite annoying. Some wire gates now have "hooded" noses that also avoid catching.
● Sling material: Quickdraw slings are usually made from pure nylon or nylon blended with Dyneema or Spectra. Spectra and Dyneema are both branded names for UHMWPE—Ultra High Molecular Weight Polyethylene. Spectra and Dyneema are always white and only white; any color is the nylon blended in. They are inherently stronger than pure nylon, so they can be made much lighter and narrower while providing the UIAA-required minimum strength of 22 kN.
● Sling length: Quickdraws range from 10cm to 25cm long. The standard short length is 10-12cm. This works in most situations when the route is relatively straight. The standard medium length is 17-18cm. This is useful for reducing rope drag, especially when routes are more than 12 quickdraws long or if the rope is not traveling a straight path. The standard long length is 25cm. These are useful under certain unusual circumstances on a sport climb, such as an out-of-reach bolt during a redpoint attempt or a poorly placed bolt that is causing massive rope drag. These are also useful for traditional climbing when you are placing your own gear.