I have several friends who have DC at LAB. They're all pretty happy with it. Since the school got its Ofsted Outstanding the catchment is now very small so you will need to really do your homework in terms of where to live to try to ensure a place. Although as you probably know, the school operates a banding system so that 'skews' distance places.
DC sit the admission test at the beginning of September. If you're looking for places via the wait list though, I think the banding no longer would apply but the school can advise you about that.
The only 'downsides' I've heard from my friends is that the school is limited for outside space (I believe the DC do at least some of their PE sessions off site) and some of the communal spaces are small. If you have very sporty DC, this may be an issue.
They also operate a 'small school' system which means the DC are put in houses and spend a lot of time with a relatively small number of peers. This has it's pros and cons.
It does the IB for sixth form which again has its pluses and minuses.
It's a relatively new school and has only had one cohort sit GCSEs so far which may put some people off.
As I say though, most of the DC I know there are pretty happy. It's certainly regarded as one of the 'better' state secondaries in the area. To the point where people are now actively moving to try and secure places.