I side with being current. Sans any bug additions, current saves time in a few ways.
One, the content of many posts are generally about the current product - not always certainly. I scan this every day looking for features I didn't catch, new technology additions and the like. If I stayed on past products, I would have to search in a more defined approach.
Two, the developers of the latest technology, aren't resting on their past success, or they might experience the customer shift that blackberry experienced... meaning that they listen to customers and incorporate changes that improve the user experience so to speak. I find that those simple changes can make improvements in time..
I also have another driver, and its not rational. I hate looking at a post and then say WHAT??? I wish I had that...
If the cost is important enough to anyone, I might suggest that staying out of debt is a great consideration. Especially going from one version to the next. I would rather anyone sleep well at night, have less contention in money matters with others than to get the next new shiny thing and have to pay any consequence which that decision brings.
Best Regards,
L