How exactly did you do a clean install? (and why)
And MSE isn't recommended by whom exactly?
Looking at av-comparatives current 'real world' tests, they call 95% detection "non-competitive", they also talk about using Win7 as their test platform, then mention "tested against out-of-box protection", then acknowledging that Win7 has no out-of-box AV protection and Win8 has... it's just bizarre (why not just say "tested on Win7 with MSE"... footnote, Win8 comes with MSE and it is confusingly called "Windows Defender"). They then acknowledge that 100% detection doesn't mean that something is a perfect anti-virus and that it will still miss stuff in the wild (which is perfectly true), so how can they call a 95% detection rate non-competitive? Are they guaranteeing that their tests are accurate within 5% in the real world? Really?
I personally think that there's an effort to discourage people from using MSE / Windows 8 Defender. Anti-virus vendors obviously don't like the idea that there's now built-in AV in Win8, but I wonder whether AV-test/comparatives have bees in their bonnets about Microsoft becoming popular in this arena, or they're just being paid to bad-mouth it. For example, the "Which?" magazine (a publication in the UK with a generally good reputation for product testing) did an article on AV effectiveness, asking the useful question "is free protection good enough?". The article was an utter farce - they didn't document their testing techniques, and they gave every free anti-virus package low ratings and gave Norton top marks.
Back to AV-comparatives. There's also no information to what "blocked" and "user-dependent" means. Does it mean the entire malicious URL was blocked from loading at all or does it mean that the malware was detected and automatically stopped from loading on the target computer? If it's the first, then I think they need to re-establish the remit of the test. Website blacklisting isn't a very effective technique against malware. It's the first line of defence that an anti-malware package can have, but because a legitimate site can be hacked or is hosting a malicious ad banner, website blacklisting is known to have very limited effectiveness. I would rather see separate tests of each layer of defence than having the overall test skewed by one vendor's excellent site black list but possibly terrible AV engine. Does MSE / Defender even have a website blacklist?
Looking at av-test, I have no idea how they calculate the score for each category, and I would dispute their definition of "0-day malware attacks" if they think the industry average effectiveness for blocking such threats is 91%. This is what a zero-day attack is:
http://en.wikipedia.org/wiki/Zero-day_attack
The scary thing about a zero-day attack is that any Internet-connecting product is at risk from something that the vendor doesn't know about until after the attack has started in the wild, as opposed to a discovered vulnerability which is reported to the vendor and sufficient time given for the vendor to fix the problem before the vulnerability information has been published. There's nothing to stop a security product from having a zero-day vulnerability, it's just as likely as any other piece of software out there.
And they're talking about "inclusive of web and e-mail threats"... as opposed to? I would also dispute that the industry average for detecting "widespread and prevalent malware" is 100%. The av-comparatives website mentioned "95%" being "non-competitive" for threat detection, I would be surprised if any AV product was 95% effective against the total amount of threats out there, I would be quite happy if one was, let alone almost all of them!