I looked into this German item, but it's not available here and is rather expensive. I ended up with the Rockwell Blade Runner. Go ahead...laugh. The first few times I used it, I was ready to throw it away. Then, I switched to the Bosch blades and found that it worked rather well. If you want it to cut straight, you really need to cut 3/4" or less. It will cut a 2x4, but if you don't use a long enough blade, it won't use the guides and the blade will bend and cut crooked. I had to cut a single tile in half to make a glue gun stand and I was quite impressed when I used the ceramic blade and cut that sucker perfectly! Feed slowly, watch the great result! I use the scrolling blade to cut curves and it works rather well. I taped several layers of 1/4" MDF together and made a stack of zero clearance inserts for my miter saw.
If I had a bandsaw, I might not need the blade runner. However, I find it much easier for small, precision cuts than a multi tool or jigsaw. It doesn't have the overcut of a circular saw/table saw.
your best bet is to find a unit that someone else hated, buy it some new, quality blades suited to the job you're doing then enjoy your bargain!