MS SQL backup and restore on VM

I have couple of virtual machines which run SQL 2008. Are there any cons to backing up SQL using the AVVI, is there any drawbacks in terms of restore or should I stick to backing up SQL server using the traditional approach ?

I came across a few forum discussions that along with the VM backup I need to create another job for transaction logs. 

Can anyone suggest whats the best approach to backup the SQL server 

Thanks in advance.