Advanced are great for the newer models for sure. Excellent communication, good shipping and the kits are good. They seek out some decent quality aftermarket suppliers too. Not so good for the older stuff I find where I prefer Britcar or LRDirect.I think they are one of those places where they have a big online presense but maybe there are only a handful of staff. I must admit I haven't ordered from them for a while.
For newer LR service stuff I use Advanced Factors, they are members on loads of the forums and service is excellent. If they don't have something they ring you and they tend to do kits that include everything that you forget but wish you;d ordered like fitting kits and new bolts etc.