I would add that as far as widespread acceptance goes this sort of UI stuff can easily be underestimated and is most often all that a lay user sees when forming an opinion. I can't think of another situation similar where you are expected to configure options without some degree of reference.
Anyway, just my ten peneth, hope it's of some use. :)
The initial blockchain download can take a while and there are a few ways to speed the process up, but right now development is focused on making the Sia platform as stable as possible. In the mean time several people are providing links for partial blockchain downloads that may speed up the process, but be careful where you get the file if you decide to go that route.
As for your other questions there were also price estimation issues with the old version. Those should be mostly fixed with the latest release. The main issue is that when you "buy" storage you are really just setting aside that money to use for future file contracts. Until you actually use that money, the price of storage will fluctuate with the market. That means the 10GB worth of storage the UI showed you a month ago is let's say 8-12GB worth when you go to use it.
As the market matures and price stabilizes this should be much less of an issue, and the old version of the UI greatly overestimated the cost of storage which is why it locked up so much. The bright side is that any SC you don't use at the end of the contract time will return to your wallet. I believe this is 3 months by default. In the mean time you can use the money you set aside to upload files as you normally would and be charged the going market price.
ah does that mean that we can customise the amounts in which files will be spilt do i get that correctly?
and what exactly do you mean by "encrypt it by using whatever scheme you want"
the algorithm oder the key