I love my KA - but I sure wasted money on some of the attachments. I've had mine for about 2 years now and this is what I've learned (aka: my opinion).
Trick one is to shop around for what you want/need .... www.kitchenaid.com
is the most expensive place to buy anything (except they may be the only source for some things and sometimes will match the prices or other on-line sources on the mixers). www.chefscatalog.com
has some good deals, but I have found www.cooking.com
to generally be the best place for the lowest prices.
I got the accessory pack that has the food grinder, slicer/shredder, and fruit/vegetable strainer. True, the food grinder is plastic and may/probably will eventually crack, and with a good food processor with 4 slicer/shredder disks you can do the same thing, and as for the fruit/vege strainer either a hand crank food mill or a strainer and a wooden spoon will do the same job - but, hey - that's no fun!
I do about 5-lbs of meat in the grinder each week - no cracks yet. But, I don't put the Godzilla twist on the retaining ring when I assemble it ... and have never had to use the wrench to take it apart. I also got the sausage stuffer attachment to go with it and make about 5-lbs of sausage each month. I usually save about $1/lb making my own sausage ... but if I only break even at least it is seasoned the way I want it, and I can make some off the wall combos.
The slicer/shredder I love for large batch jobs. I like it better than a food processer because I don't have to keep stopping and taking the FP apart to dump the bowl when it gets full ... my only limit is how big a bowl I put under the spout.
I must admit that I have never used the strainer ... I generally reach for a strainer and a wooden spoon. But, this year I'm going to try using it when I make peach and apricot preserves for Christmas.
As far as the pasta maker (extrusion die) set that works with the food grinder - it's a waste of money as far as I am concerned - the only dough it will handle is a soft egg pasta dough. And, it's kinda funky to work with because the dough is so soft.
I also got the pasta roller/cutter set - not bad, I like it, but I would go a different way if I had it to do over again. You get 3 attachments - the roller and 2 cutters (Fettuccine and Linguine). KA has now come out with a ravioli attachment (another $125). But, that's it. If I had it to do over again - I would buy an Imperia 150 with the electric motor (gives you the roller and 2 cutters with an electric motor for the same price as the KA attachments) plus you can by additional cutters for $15 for single (1 size) cutters, $25 for double (2 size) cutters. In other words, for about the price of the KA pasta roller, 2 cutters, and a ravioli stuffer - you can get a roller, electric motor, 10 cutters, and a ravioli stuffer. Best prices I have found for this are at www.pastamakers.us
Humm ... guess I have everything but the gain mill (can't justify the cost), the citrus juicer (don't use one that much and already have a good hand model), can opener (can't see having to drage the machine out to open a can when I have two good ones already), the water jacket is WAY over priced (got a plastic tub at the dollar store that works just great and was $65 cheaper) ... and heven't seen a need for the food tray (you can only feed just so much down the feed shute at one time anyway).
I think the extra bowl is an excellent idea.
I, too, have VERY limited space ... I have virtually no counter space and had to get a 3-shelf rolling cart to hold my KA - which gives me storage space for the attachments and 6 6-qt square containers.