It is a good Idea. If you talk to people who have owned those pools with the inflatable top ring you will find out that it does stay inflated like it is suppose to. Good-Luck!
the filter will work but the ponds dont last forever and make sure to double cheack for leaks i started to fill mine up and found two leaks and it was brand new out of the box but i fixed them and am refilling it up..... and i wouldnt keep it for a permanent pond they are ugly and fish dont look good against the backround heres a link to the thread i started check it out new pics coming soon
i have a couple new pics uploaded for you guys.... and to deal with the question of how long they can stay filled with water i had one filled for almost a year before i took in down when we moved it was for my old roomates kids to play in and they were rough they splashed alot of water out but never popped it