What is your goal in getting a stringer?
Are you straight looking to save money thus need to look at payback time of buying a stringer? Maybe looking to decrease the cost of trying different set ups so you can try more things and maybe more expensive strings even if you don't save money overall vs now? If so, how often do you need to restring now? You don't mention how many kids you have or how often they or you need to restring.
Are you looking to just learn something new, maybe get the kids more involved in their sport and learn more about strings and stringing and cost isn't really a major factor? Can you see you kids earning extra money by starting to string for their and your tennis friends?
Any of those reasons are valid. If you are strictly looking at stringing for your own needs, only have one kid and are looking to decrease the cost of you activities a simple dropweight, flying clamp machine can't be beat. They are not difficult to learn to use with a bit of effort and if the kids decide they want to play soccer instead and your hip goes out you can sell a $150 machine for $75 the whole experiment is pain free.
If you are looking at a long range full family of junior tennis and adult tennis with maybe a side biz for your kids with little doubt of changing your mind then go for the $1,100 machine IMHO.
I have a Klippermate 2 pt dropweight that works just fine for me. However I'm an adult and the only one in my family that plays regular tennis. I knew zero about stringing a tennis racquet before finding this forum just a year ago. There is all the info you need on this forum and YouTube.
If I was more of a string breaker and I had a couple of older kids playing I'd probably go for something like the Alpha Pioneer DC Plus at $429 or something similar. It has a 4 pt mounting system and fixed clamps at a still reasonable price for a hobby. The dropweight system doesn't bother me at all and I like that a dropweight is a constant pull.
That's my 2c. Here is a link to my first stringjob:
http://tt.tennis-warehouse.com/showthread.php?t=313693&highlight=klippermate I've done less than a dozen stringjobs, on a variety of racquets, since getting my stringer and am down to about an hour on my last one...and that was a full natural gut job. I think I could do a multi, on a racquet I've strung before, in about 45 mins now. I'd say it takes about 6 to get comfortable where you don't need to double and triple check everything and can just start. I've now settled on and know what knots to use without looking them up (YouLitles vid for starting knot and Drakulie's for pro knot) and generally understand how typical patterns work. I say definitely go for it whatever machine; I enjoy it.