You will really enjoy the lower gearing.
The only draw back with replace the 2.28 with a lower gear ratio in a single case, is that once you engage low range, you'll now be in super low range. You will loose the ability to do 50 MPH in Low Range 5th gear. Now your best will be about 25 or 30 MPH in 5th gear.
But if the above does not apply to you, then you will definitely love it.
On the other hand, with dual cases, you can put one case in high range (1:1) and the other in low range (2.28:1) and you'll be able to do 50 MPH in 5th gear Low and be 47:1 in 1st gear as FIREBALL mentioned above. Then when you need to Crawl, you can engage both cases into Double Low, and you'll be 108:1. Also Dual cases allows the option of using two transfercase mounts which stiffens the drivetrain with more support.
The advantage of just doing a gear set is that it is much easier and cheaper to install. You don't have to modify your floor board and carpet, won't need to modify your drivelines, speedometer cable (if it applies), or your 4WD shift light indicator wiring.
If you are going to use the 4.70:1 gears in your transfercase, then I HIGHLY recommend using our 4.70:1 Gears. I am telling you this not as an employee at Marlin Crawler, but as a friend. Marlin Crawler Invented the Total-Spline™ technology and it has been simply amazing. Also unique to the Marlin Crawler design is that we have the same 2-degree taper on the shift hub teeth to prevent accidental gear disengagement, and we also have an advanced oil circulation system to aid with cooling.
To read more about the advantages of using a Genuine Marlin Crawler 4.70:1 Gear set, please read this following thread:
Marlin Crawler 4.70:1 Gear DesignIf you wish to learn more about our Exclusive Double-Row Bearing Dual Case Adapter, which has proven itself as the most reliable Dual Case Crawler in the World, the please read this article:
Understanding the Success of the Marlin CrawlerHope this information has helped with your decision.
Regards,
BigMike