There are a number of different ways you can watch streaming film content using a PS3 in the UK. You can use Sony's official video store on the Playstation Network, which has a decent selection of - in the main - new releases from the major Hollywood studios. You can buy or rent titles and watch titles as they are downloaded - effectively streaming them from Sony's servers. I can't tell you how well this system works as the prices - for me at least - are prohibitive. Rental titles are around £3.50 on standard definition and £1 more for high definition. Given that the file sizes for HD movies appear to be around the 1-2Gb mark, you're obviously not getting blu-ray quality. These prices are roughly comparable with what I can get from Virgin Media cable, where I believe the bitrates will be a tad higher. So, no deal. [NB: to be fair, I think there are also some budgets titles, but I have enough junk on DVD on my shelves - see later post!]
As a quick aside, can I just mention the social integration of these apps. Both MUBI and Lovefilm feature facebook integration (Lovefilm has twitter too) but neither service appears to work at present. In theory, watching films via MUBI and Lovefilm should automatically update FB and Twitter, alerting your friends to what you're watching (this is optional, for obvious reasons!).
One point worth mentioning regarding streaming to the PS3 is that each of the services I've mentioned do not stream all titles via both their websites and the PS3, as titles need to be licensed specifically for the latter. For example, titles on Blinkbox from Sony Pictures are not available for streaming on the Playstation. I have to wonder if this is a legacy of the relative newness of consoles, STBs and connected TVs and that future licensing deals for online streaming will incorporate all potential targets.
So, a decent range of titles - made available in a number of different ways and all legal and largely affordable. And a reason for film lovers to perhaps get rid of, or cut down, on expensive cable and satellite TV packages? Only time will tell.