It is great for viewing and creating small datasets. Viewing larger datasets required a surprising amount of effort in terms of tiling and converting. The tools built into Google Earth were never very good and people were pointed at server products. This was completely at odds with the simple ethos of Google Earth and often lead companies to invest in expensive ESRI products that offered Google Earth support!
Google are concentrating on server products with web interfaces and GE never fit into that. It is fantastic for professional users but Google have no idea how to sell to those kind of people.