Apart from one somewhat-too-obvious mystery (possibly due to over sign posting), I think I can say it was a success. Martin Freeman did an excellent job as ex-army-medic Dr Watson, and as said elsewhere, made the most watchable Watson I've seen. Resetting the series in the here and now is an interesting decision, but (at least partly due to a strong sense of place in London) it works. This is totally the Sherlock Holmes that Conan Doyle would have written if he'd had to cope with one way systems and mobile phones and the Internet. The first hour didn't really put a foot wrong, and though the last 30 minutes was a bit slower, in general this is something worth watching.
So, full marks to the Dr Who team (Moffat, Gatiss, Vertue) taking the time out to do this too.
(The only thing missing was the obvious modern line that my title inverts. We did spot one particular point that it could have been dropped in.)
ETA: there may be spoilers in the comments