I feel they are late in introducing this feature...I was a DropBox user since beginning and collected 10GB more freespace by invites .
Recently slowly i have shifted my alliances to Skydrive after giving a try on Google Drive. Althgh am one of the Microsoft hating club, Skydrive is so fast and happy with its services. Only worry for me on Skydrive is Microsoft's history of scrapping the project even when its successful. Hopefully they don't do it.
I was a Microsoft Live Mesh user. After the idiotic decision to shut that down in favor of SkyDrive, I decided to just drop Microsoft completely. I had been using Dropbox and Mesh side-by-side. Mesh was unique for syncing files and folders in place, without having to move them to a new place.
Overall I always found Dropbox to be faster and more reliable.
Recently slowly i have shifted my alliances to Skydrive after giving a try on Google Drive. Althgh am one of the Microsoft hating club, Skydrive is so fast and happy with its services. Only worry for me on Skydrive is Microsoft's history of scrapping the project even when its successful. Hopefully they don't do it.