I want to use a Mesa IO card

I want to use a Mesa IO card to get better performance from my mill.
I see the set up wizard supports several boards but which one is the
best choice? Best support, easy to configure and not to pricey.

first you need to know what type and how many connections you will need etc , number of steppers , relays , limits , spindle motor requirements etc
if you can get away with less than 48 pins in total then theirs the 7i43 this connects to the parrell port ... or if you wish to go to a internal PCI Card then you have the 5I25 or the 5I20

give some details on what you need and what type of mill you have ... stepper motor or servo .. spindle motor speed control needed or just switch on and off with relay etc

I have used both 5i20's annd the 5i25 with the 7i77.They both work well.My take on things.

5i25 and a 7i77
pro's
as a package,inexpensive
driver is already loaded
board is layed out well
inputs and are a snap to set up
easy to set up additional i/o with serial mesa i/o boards
additional i/o on 2nd connector can be set as inverted signals and opendrains(on 5i25)
easy to run small relays with dc output
led's on the board are helpful
cons
not a whole lot of info available for setting up the 7i77,not hard when u figure it out
out puts cant be inverted,which makes using them with standard opto boards impossible
2nd connector cannot be setup to be all outputs
needs 24 out puts on the 7i77 or the ability to freely map the i/o like the 5i20

5i20 and 7i33
pro's
every pin is freely mappable
can be used with standard opto racks
lots of setup info available
seems more flexable
with the right expender card,you can use the serial i/o boards
cons
more expensive
driver has to be loaded
its flexability has a dark side,more work required in hal
uses ribbon cables
if you need more then two axis of movement(assuming you have a mpg and spindle),you need another 7i33 or go to the six axis card.
serial i/o requires a special card.

They both work well,it depends on your needs.

One small quibble:
The second 5I25 connector _can_ be all outputs (or inputs in any mix).
(5I25 firmware is identical to all other HostMot2 firmware in this respect)

I could only get 14 of the 17 outputs to work,output 24 thru 27 would come up with a "does not exist" message and I listed all the available pins in hal show and according to halshow,the outputs on these pins dont exist. What am I missing?

Do you know the firmware name?
There is a bug with the 7I77x2 second connector
firmware which will make pin 24 unavailable if you have more than
3 encoders enabled

If this is the 7i77x2 bug,

freeby.mesanet.com/7i77x2.bit

is a corrected bitfile
(The bug has also been fixed in bitfiles in the 5I25 software support zipfile)
You will need to use the mesaflash utility to update your 5I25

Thanks to all for the input.

I came to believe the point of using the Mesa board is improved performance via the FPA being configured to do many of the
tasks other wise performed in software hence faster and more precise motor drive output pulses also greater bandwidth for
encoder inputs.

I assume one still uses a HAL file to configure the IO when employing a Mesa board.