I have had Singer Futura's for 30 years..my first was the CE100...it is still going strong. I handed it down to my daughter. It is absolutely possible to use the old machines, all you have to do is use a computer with the old operating system..any computer tech repair place can easily install Vista or windows 7 on a new computer for very little money.It is not a bad idea to have a computer dedicated to your machine and not online..you put your designs on a thumb drive from your internet connected computer and transfer to your dedicated computer.
As for manuals on line..I have gotten a hard copy with every machine I've ever bought...right up to the machines I have now, which are the SEQS 6000. I think having the manuals on line is a courtesy for prospective buyers to be able to see the machine??
The needle is adjustable and it did come with a 1/4" foot, as well as many others.
I like the ease of use of the software for enlarging/decreasing as well as importing fonts and combining 2 or more designs..it also has a feature that lets you quadruple the size of the hoop for huge designs, you divide the design in 4 parts and line up the points, then stitch one quadrant, rehoop, line up your points, continue, etc..the largest designs I've done have been the center for a tablecloth that is about 30" x30"..it is called "multi hoop" on the quintet and seqs600.
I know everyone is loyal to their own brands, but for me, you can't beat the combo of features, price, and ease of use.