mac mentor, matco determinator and cornwell taskforce? are all the same as otc genisys.
make certain the power button is red. older models had black buttons and have slower processors.
the 4.0 is needed to run newer stuff (european). im not sure if 4.0 is needed for anything domestic based. 3.0 is fine to get you going. However, 4.0 is a vast improvement over 3.0.
the smart cable does away w/ all the little individual cards/chips for the scan tool. best price i have seen on them is 200 bucks. if you use the machine often it is worth it. there is some european stuff that you need the smart cable for. in addition, your machine has t be up to 2006 spec or newer to use the smart cable
update wise, the otc stuff is not bad price wise. thats actually their strong point in prices.
750 gets you updates to 2009 for air bag/abs and domestic and asian along w/ the 4.0 software and memory.
if you need the smart cable--200 to 250 range i cheapest i have found
if you need european, update straight to 2008 for 300. if you want obd1 european coverage, you can find cable kits packaged w/ a 2005 disc from 120 to 300 private party or 500 range from a seller.
the comparable snap on machine i would say is the solus. used you may find them around 1000. the european software is about the same price. where snap on is more expensive is the updates. you are looking at 1k a year for update. if your solus was last updated in 2007, you are paying at-least 1500 to get it up to spec.
when i bought a scan tool for side work/home use--the biggest sway for me updates. as that will nickle and dime me. Paying for updates at work i don't mind as it gets used all the time. for home use,i didn't want the updates eating into my side work profit. As i liek the snap on tool better since im use to it. however, the otc im starting to get the hang of and have no complaints really.
i just recently paid 375 for my matco determinator scan tool that had asian/domestic/euro and a bunch of obd1 cables. i have purchased the smart cable and european update. yet still need the 4.0 and domestic/asian/airbag update. I should have bought that first as i cant use my smart cable or euro update w/o the 4.0 stuff or getting my system past 2003 specs. All said and done i will have around 1300-1500 into the scan tool. However, i have every cable there is-- all the obd1 for asian/domestic/ euro as well as the heavy equipment.
used i have been seeing these go for around 1k on ebay. most of them are 4.0 spec, just no smart cable or euro coverage are in them. plus they are lacking all the cables. so i would think you would be able to get up and going--but will eventually have to find stuff you need which will put you likely around 1500.
i really cant think of another scan tool for "cheap" that does what all you want. The 500 or less stuff seems to do either abs and global obd, or airbag and global obd. they wont touch obd1 nor will they be "dealer" level codes.
i cant comment on the ethos as i have never used it.
hope this helps
mike