I'm surprised you didn't get an answer to this yesterday. I saw it through my IFTTT notification, but I taught all day and didn't have time to give it a go. I think, though, that you should check out an earlier post on this topic, here. That post is more about perceptions of empire, but it's relevant to your question.

In terms of actual benefits, that's very difficult to assess, because of the same issues raised in the linked thread: the empire was huge, multifaceted, and difficult to define. It's at once a great bureaucracy, expanses of territory, people in both Britain and around the world, and a way of thinking and talking about oneself and others. It's also difficult to answer because it's not always clear what a "benefit" is, or the extent to which a particular benefit is the result of domestic or imperial processes.

For example, we could say that British imperialism in India helped develop the Lancashire textile industry by providing a market for its products and a source for its raw materials, an uncontroversial view. However, is that really a "benefit" to the actual workers in the factories? That factory laborers early in the industrial revolution had miserable lives is also an uncontroversial view; indeed, the standard of living debate that dominated a lot of British social history from the 1960s to the 1980s--and is still around, to an extent--was for the most part decidedly settled in favor of the "pessimist" case. That is, historians studying living conditions, wages, and so on, found that British industrial workers' material standards deteriorated, and bottomed out in the "hungry (18)40s," when many scraped by on borderline starvation diets. Floud et al's recent synthetic monograph The Changing Body, a follow-up and expansion of an earlier work called Health, Height, and History, provides in my view the best evidence for the pessimist case: people got shorter during industrialization, and heights didn't reach their previous levels until substantially later in the nineteenth century, though we're now taller than ever.

All that said, it's also pretty clear that the empire had substantial economic effects in Britain: not only were colonies import and export partners, but many industries developed in Britain around specifically colonial trades: Liverpool and Bristol, for example, were both major slave trading centers, London had a substantial sugar-refining industry, and Birmingham exported a great deal if its metal goods to colonial markets. These and other trades also generated and helped fuel a large shipping industry, including ship construction, repair, and supply. Beyond shipping itself, the City of London developed from the seventeenth century a large financial and maritime insurance sector, which still exists to this day. People across Britain also consumed colonial products like tea, coffee, and sugar in particular, but later in the nineteenth century many others. You can see a selection of these products from the King's Christmas Pudding in 1928. By that point, a policy of imperial trade (called "imperial preference") was more developed than at any time in the past, but you can still get a sense of the range of colonial products consumed in the metropolis.

So, I think we can say definitively that the empire had many effects on Britons, but whether we want to call them benefits or not is a more difficult question. It is the case the living standards improved, particularly after 1850, but the extent to which that's a direct effect of empire is difficult to say.