I as well as many others received an email from Apple today announcing the availability of OSX 10.10.3 beta which includes the new Photos application. If interested you need to sign up through the beta program.
Photos is the new replacement for iPhoto and Aperture. It is reported to be more capable than iPhoto, but may not have all the features a professional photographer would want and found in Aperture. The big advantage is that it makes your entire photos library available through iCloud so that photos you take on your iPad or iPhone can be edited on any of your Apple devices, and those edits are instantly seen on any of your other devices. That advantage could come at a significant price, since it’s an all or nothing deal. If you want all your photos in one library shared between all your devices including your iCloud account, you could easily exceed the 5Gb free file storage you have on iCloud. Of course you can get more space. 20 Gb is only $12/year, but 1Tb is $240; more that twice what it is on Google drive or Dropbox.
The easiest way to get around this is to split up your existing large iPhoto library into smaller ones and only share the library that has the most recent pictures you want on all your devices or share with others through iPhoto Sharing. On the other hand, $12/year is not so bad and can probably accommodate 2000 pictures or so depending on resolution.