Toys made of silicone will last a lifetime with appropriate care. They can be boiled with no ill effect, many people boil them to sterilize them, so they aren't going to melt under normal circumstances. All you have to do to keep them safe is not directly expose them to dangerous materials, such as the chemicals in jelly rubber.
As for whether the shape will work for you, there are many reviews on every product here, so try to find someone who has the same tastes as you and who also reviewed the product you're considering.
If you want a longer double dildo, consider the Sonic. It's significantly longer than the Pink.