Not sure on the others, but avoid Jasper or ATK. My Jasper 22RE has burned well over 1 qt of 20W-50 every 1000 miles since I got it.
It's at about 15k miles now (well past any break-in period) and still doing it. Junk.

I'll second staying away from Jasper, their warranty sux (especially for what their engines cost) and in my experience they are a PITA to deal with.

My Jasper 22re was ok for about 5k and then started leaking oil like crazy from the junction between the head and timing cover. I had to fight them to pay labor charges for the repair at their "preferred" shop (couldn't do it myself without voiding the warranty) and it took a month once was all said and done. It is now out of warranty and has about 20k on it and is burning 1qt of oil every 800mi or so <img src="/forums/images/graemlins/angry.gif" alt="" /> I called Jasper and their suggestion was to run high-mileage 20w-50 in it and that should "fix" the problem...

I'm planning to ditch the POS as soon as I get my Supra put together and will be rebuilding my extra 7mgte and dropping it in, hopefully in the next year or so.

'87 4-Runner--DD/wheeler, 4.3 swap coming soon
'89 Supra--E85 powered 2jz NA-T Swap, 533rwhp 497ft-lbs
'89 Festiva, turboed BP swap powered by megasquirt