Now that I've read all the post I'll chime in. I have seen the demo at the quilt show for the Alto cut; I really like it alot and could see how it would be great right along side my Accuquilt Go. Don't have the money yet so I'll wait until next years show.
As far as the HST go don't let the 7/8 bother you. Add an inch and then square it up to the size you want. I think especially in the beginning when you are learning how to do them it's the best method. There are a few different methods to making them. I like the one where you take two squares, put them right sides together and sew down the middle and then I square it up to the size I need. You waste very little fabric this way and it's worth it because sometimes no matter how hard you try they come out to small. There is also triangle paper you can buy and some can be downloaded from the net for free. I have two software CDs to make my own.
As far as squaring up, if you are talking about HST; you can use any ruler to do that. To square up a block you can use any ruler slightly larger than your block. Find the center of your block on all sides and then trim what is sticking out from under the ruler. There are alot of great rulers out there but some are designed to do only one thing and I'd rather spend my money on things that can do more than one if possible; unless it really does make my life easier by alot. I'd look at the size of block you are thinking about making and then get a ruler larger than that at least by a few inches. I really like the ones that have the 1/8 marks on them as well; not all do.
The Accucut Go isn't just for appliqueing. They have dies for everything. In the beginning what might do you well is the strip dies; you cut the strips of fabric and then you can cut them into triangles, blocks ect.
I know, there is so much to think about and so many options out there it can be over whelming. Just take your time and try to research things to see if you think it'll benefit your needs. Normally if you search on the web you'll find a site where people have written their reviews on different things. Fons and Porter also have lots of rulers and if you go to their website you can get all kinds of infor on rulers, etc. Good luck