ber0ni
The DrumIt Five comes with 4GB of on board storage. They will be implementing 3 x lossless compression, so in one way you will have a lot more memory then 4GB to play with. Most people out there will not always being loading sounds on to the Unit, as they will have their own personal favorite kits. So i don't think having a USB/Flash memory stick is the most essentially thing for this kit.
OS updates is something that was planned from the start, and will carry on through DrumIt Fives life cycle. Just like most things out there now, everything has updates to improve things and clean out bugs. As an example my Xbox 360 is a totally different machine now, to what it was when i brought it at launch. I was impressed when i first brought it, and i could see the potential for it to grow to something even better, and that is what will happen with this kit. Everything has to start some where, otherwise it would never come out of development. I am very impressed with this kit, and to see what it has coming down the road to add new features makes me very excited.
The Unit's UI is very easy to get around, and the sounds are some of the best i have heard from an e-kit. These are real drum samples that have been created from scratch, a lot of blood, sweat and tears have gone in to them, to make them sound as good as possible. 2box will keep release new sounds for end users to download free of charge from the website as well.
At the end of the day everyone has different preferences when it comes to products. You have to go with the one that you feel fits your needs, and just enjoy it

Thanks
Scott