Great question!
I think that leaving the category in place makes sense, but not at the beginning of the page title. Having the category can help further specify what the page is about, especially if there are links on that page back to that category. Here is an example:
{Product} Reviews | Best {Category}
In this format, you are stating the keyword or phrases you want to rank as the highest priority, and having the category be secondary. If you don't want to include it, you could also use the site name at the end as an alternative:
{Product} Reviews | Product review worded differently - YOURDOMAIN.com
In this format, you have a higher density of your keyword in the page title, while not overstuffing it. If you have a lot of reviews that rank, this can also help with brand or site recognition.
Hope this helps! Keep in mind, optimise around the user, and what your best guess is that they will type. Check in your analytics account to see what phrases users are typing, and structure your titles around that format. The structures above are just best guesses, but the analytics data will give you a much clearer picture.
