OP has a Deere 3038e. Pretty light tractor @ 2,175 pounds, bare tractor. About the weight of a Kubota B series. I think OP would find the TSC CountyLine Subsoiler adequate but the ETA subsoiler with shear bolt protection is the wise buy.
OP will not be able to pull either the Tufline nor Dirt Dog subsoilers more than 10" deep. I am pretty sure neither brand Subsoiler has shear bolt protection, so there is the potential for OP to pull the light Deere 3038e over backwards should unprotected heavy Subsoiler encounter something immovable under ground.
I am old and cautious. I would not want a Subsoiler lacking shear bolt protection unless my tractor had Draft Control to prevent tractor from being pulled over backward. Commencing at about 60-horsepower most tractors have Draft Control standard. Draft Control is a seldom ordered option on <60-horsepower compact tractors.
I speculate the TSC/CountyLine (by Tarter) Subsoiler would fold before the tractor went vertical. Not bad.
TSC has a liberal return policy for CountyLine.
Both Dirt Dog and Monroe Tufline make quality implements, I have one implement from each.
Dirt Dog is the manufacturing subsidiary of Iowa Farm Equipment. I believe Dirt Dog manufactures every implement on offer. I have ordered several implements from Iowa Farm Equipment, including my Dirt Dog APP / Field Cultivator. Customers Service has been excellent.
OP has not revealed what uses he plans for a subsoiler. For many tasks a three tine or four tine APP/Field Cultivator may serve better at just slightly increased cost. A three to four tine Field Cultivator has about the same draft force resistance as a single shank Subsoiler pulled 12" deep.
ETA offers Field Cultivators too.
IFE LINK: Iowa Farm Equipment
I am old. I get a kick ordering heavy farm implements over the internet, and three days later, a sixteen-wheeler from NC/KY/IA arrives at the house and delivers same. If you're looking for quality, check out
Titan Attachments—selection is so much better than 'the old days,' and no implement I purchased new via the internet arrived with rust.
Photos #1 - #2 Dirt Dog APP
Photo #3 Monroe Tufline Disc Harrow, 20" diameter pans.