Like everyone writing here, I love acers, but I do agree that they can be tricky. Currently, I have 20 (14 different cultivars), all in containers, some now seven years old, but that's down from 24, as 4 have abruptly died in the last two years.
Here are my conclusions from the last six years collecting & growing:
1. even small ones don't mind freezing weather, as long as they have some shelter (eg against a wall) and the soil doesn't freeze solid
2. they HATE wet feet, and will almost certainly die if they spend a winter sitting in a saucer
3. watering in spring at leaf-opening is perhaps the trickiest thing: not too much, and not too early
4. though 'dappled' is often mentioned, they can take lots of sunshine and will respond well in terms of growth - provided it's not all day and particularly not mid-day sun
5. to produce the deepest colour in the purpurea forms, lots of sunlight is actually essential
6. so, for reasons of 4&5, north-facing isn't ideal
7. exposure to wind, particularly in early spring, will wreck their appearance for the whole year, and may kill the plant if you're tempted to overwater to address leaf dessication
8. they love leafmould mulching - and who wouldn't :)
9. if they drop leaves (early frost / overwatering) all is not necessarily lost, even if no more re-grow until the following year, however, if leaf-loss is accompanied by white speckles on a darkened trunk, it's a goner
10. seaweed extract is reputedly (per advice @ RHSChelsea & Hampton Court) a better fertiliser than growmore or Miracle-Gro-types .. so far so good
Anyway, I hope all that helps. I'm still learning as I go, but the three most important points for me so far are water, water, water
