Load Balancing
Google Cloud Platform's Compute Engine (GCE) recently added a Load Balancing feature. It's lower level than ELB (it only supports UDP / TCP, not HTTP(S)).
Regions
GCE has feature parity. AWS Regions correspond to GCE Regions, and AWS Availability Zones to GCE Zones
Autoscaling (CloudWatch)
Google Compute Engine does not have autoscaling, but Google App Engine does. Third party tools such as Scalr or RightScale are however compatible with Google Compute Engine
Disclaimer: I do work at Scalr.
Private Cloud
Did you mean dedicated instances? Those are not available in GCE.
If you meant VPC, then you can use GCE networks to achieve isolation. You'll also wish to disable ephemeral external IP addresses for the instances you want to isolate.
Persistent IPs
GCE has persistent IPs, they are called "Reserved Addresses"
Integration with other services
You will likely get better latency to Google services you use in your backend (I recall a couple presentations at Google I/O talking about Google App Engine + BigQuery).
For frontend services (Google Analytics), you'll likely see not benefit, since this depends on your users, not your servers.