"There are only two hard things in Computer Science: cache invalidation and naming things."Put together the pieces and you can quickly ascertain that caching is a tricky area to deal with and something that should be carefully considered, and properly implemented for your Magento store.
So with this being such a difficult area to address, should you even bother implementing any kind of full page caching solution for your store? Well the short answer is yes, simply because by caching pages you reduce the work the server has to do with the end result being web pages get served to your customers faster. So even though the hardware your site is running on has not changed, you still 'boost performance' by using caching - and I put that inside quotes because actually the server is not working any faster, there is just less work it needs to do to serve a page.
The long answer is yes, but... To implement caching properly you need to first and foremost have a good foundation for your store. This means that your hosting must be sufficiently powerful to run your store well with no caching enabled. This is a key point that many people miss when thinking about a full page caching solution for their store. Full page caching is not a quick fix for poor store performance, it's a tool that should be implemented on a store that is already performing well, in order to take that performance to the next level.
When thinking about which of the wide range of full page caching solutions you want to implement, you should consider that Magento is a complex framework, and that caching Magento's pages effectively is not a straight forward task. You should carefully consider and research the available solutions. Firstly go for a solution that is mature in terms of development - so it's not a recently launched product (believe me there will be bugs!), and has a good number of releases over it's development cycle. At the time of writing this, our own solution Evolved Caching has been in constant development since February 2013 with 58 releases, so it's a mature and highly capable product which can be used on any store, however much it has been developed.
Also review the capabilities of the full page caching solution you are considering. Although there are a lot of options out there, remember that Magento is highly complex software which presents a very wide range of possible caching scenarios. Unfortunately you will probably find that many of the solutions don't cater for many of these scenarios, for instance, does the cache get updated when a time limited design on the store, category or product page starts or ends? (yes Evolved Caching does!)
You should also definitely contact the extension developers for the solution you are interested in to ask them any questions you may have. From the responses you get back, you can often get a good impression of the quality of the extension they produce. If they can explain technical details in a clear, informative way that a non developer can easily understand, then they probably have a pretty good idea of what they are doing and therefore a good product. Remember this quote?
Well that applies here too. If the developers can't explain what the extension does in simple terms then they probably don't have a great understanding of the concepts themselves, in turn the product is unlikely to be as good as it should be so steer clear.
Finally, get a trial! As a company we truly believe that if you are asking people to part with a reasonable amount of money to get hold of your code, you should give them the opportunity to trial the software first - so that's exactly what we do. If a company refuses to allow you to trial their software before purchasing it then you might want to think about the confidence that means they might have in their product.
If you have any questions about anything here, or want to get in touch with us about Evolved Caching, you can easily contact us from our store where you can also find complete documentation about our own full page caching solution, Evolved Caching.