Hi,
I did an MBiolSci at Sheffield uni - the only difference between the MBiolSci and BSc was that we did an extra year comprising a 7 month full time research project and a couple of literature reviews. I found it useful because it gives you a chance to get a proper idea of what research is actually like.
However, I have since been funded to do an MSc followed by a PhD and can say that the postgrad MSc is a lot more intensive than the MSci year is and is also valued more in the field. To contrast my MBiolSci year to the MSc - instead of a 7 month research project (adhering to UNDERGRADUATE term dates), in the MSc you work full time (i.e. all year round) - I carried out two 3 month long projects and one nearly six month project. You get a lot more practical experience in this time and don't get the benefit of long summer and easter hols...which is why it is more highly valued.
Regarding funding - if you want to do a PhD, the MRC and Wellcome are starting to favour 4 year courses comprising an MSc and PhD, so its not too hard to get funding in that respect. Also remember that some unis give out scholarships for MScs (a friend of mine got one of these at Edinburgh without even being interviewed).
But definitely - an MSci is not equivalent to an MSc, but it WILL give you an edge over other candidates with the basic BSc.