I am not familiar with Sharjah, but some colleagues live there. I guess is not that bad, since you would be going against traffic (most people live in Sharjah and go to work in Dubai each morning, creating traffic in the opposite direction).

I would assume that middle class household are above the 20k aed/month bracket mark in Dubai, so anything above 70k aed / year will give you that kind of neighbours (not necessarily westerners, which are anyway a minority in Dubai, but let's say that you won't find a tribe of 12 blue collar workers sharing a 2bedroom next door).

Low end is anything below 50k, which is dangerously near the treshold were bachelors will find convenient to share rooms, which does not mean necessarily bad, but in Dubai things can change and go bad in very short times for no apparent reason, so myself I would prefer to stay clear of those "potential" situations.

Truth is that at the end of the day, the average tenancy contract in Dubai is just one year, and if you are saving 50%, places like discovery gardens or silicon oasis may be well worth the risk, since you are not committing that much time.

You will realize the place "nature" as soon as you stay one hour in that place, so it will be a no brainer once you are here to choose where you feel confortable.
And you can't rent a place in advance anyway, as you will need on average one month for the residency to be processed, so don't waste time already looking for an house on the internet, nobody will care about you, they will only the day that you are in a position to actually rent the flat.