Vibram and Stealth have extremely good formulas and produce sticky rubber great for climbing. But with all that lingo.... What's what exactly? Knowing the different type of rubber that's used for your shoe will help you to understand your purchase better so that you can really get what you really want!
Let's start with Vibram
Classic version of the vibram rubber series, it is good on all types of surfaces. Most beginner shoes by Scarpa and La sportiva uses this rubber. Sticky and durable. Definitely what you'd want in your shoe! :)
2. Vibram XS Grip 2
The upgraded version of the original XS grip. This rubber is a lot stickier than the original rubber. It is also a little harder which makes it good for edging as well. This is commonly found in intermediate - high performance climbing shoes. Definitely worth it if you are paying a huge amount for it! Many professionals climb in shoes with this rubber. So you know you're in the right lane with this one.
3. Vibram XS Edge
A much harder rubber, it is meant for edging. Extremely durable and is meant to keep it's shape after rounds of climbing. It is still a sticky rubber but it is not as precise or sensitive as the grip series. Can be seen in La Sportiva VS (the one with the velcro).
Vibram also produces a huge selection of other rubber formulas meant for other forms of footwear. Check out their website if you are intending to purchase a pair of trekking boots and you don't know which is the best.
1. Stealth XX (Onyxx)
A hard rubber that is comparable to the Vibram XS Edge. It is meant for precision edging and durability. It also seems to get a good review for "stickiness". The 5.10 arrowhead uses this rubber.
2. Stealth C4
The most commonly used rubber for most of 5.10 shoes including the Anasazis. It is extremely sticky, comparable to the Vibram XS Grip 2 ( I think everyone is on the fence with this. Some thinks the stealth is stickier others think the vibram is. So I'd like to think they are about the same). Good for smearing and edging as well. All around versatility and performance.
3. Stealth HF
Extremely sensitive. Meant for great overhangs and bouldering problems. It is also extremely sticky and comparable to the Vibram XS Grip 2. This is found usually on high performance shoes like the Team 5.10s, blackwings and the 5.10 Dragon. Definitely a rubber you'd want to have if you are a professional climber or someone wanting to up your climbing from intermediate to expert.