I have ran both and the A4, the A5 I preferred for over all feel. It is quite a bit slimmer through the forearm. The A3 and A4 have a larger forward flat than the A5 and ride "Bags" well but the A5 has a slimmer more rounded forearm, which feels good and fits the hand better when shooting from the sling or improvised field positions where a bi-pod shot isn't a option.
For some reason or another, I guess it was the ruggedness of them and also the fact I didn't have to put the extra cash into them for the pillar bedding. I went the AICS Chassis route. The Greybull Precision stock is a excellent stock. It has the exact feel of a A3/A5 cross for a great price, I have really enjoyed the two I have. I plan on several more in the future.
Did you take a look at the Manners line of stocks?
McMillans can get spendy, by the time you get the base stock, adj cheek, adj length of pull, flush cups etc. Then have it pillar bedded to your action, your easily over 1K.
Where as with the AICS, I simple take one barreled action out and stuff the other in.
If I were to choose between a A3, A4 or A5. It would be the A5, it's a great stock.
