Overdrive Options/Gear Vendor/US Gear/4L80E

[DANTIP]

Overdrives are certainly nice for our trucks and I have struggled with my options. My 402/TH400 are in good shape but a PO installed 3:73 gears in place of the 3:08. The combination is fun in town but not as fun on the highway. The Gear Vendor solution is around $3,000 and requires me to mount some electronics and shorten the front-half of the driveshaft. The US Gear solution is around $1,800 and requires a pull-cable for engagement and shortening of the drive-shaft. The GV unit is essentially a compact 2-speed automatic transmission that can be shifted on the fly but doesn't like downshifting). I understand the USG unit can be shifted on the fly up to 35-40 mph but it's like shifting a transmission with no clutch (you have to be smooth and good with the gas pedal). The 4L80E is expensive (total can be $5,000 to $6,000), requires stand-alone electronics, requires a solution for the speedo-cable but is the most driver-friendly of the OD's.

Questions:

Are my assumptions correct ($, required installation changes, operation, etc.)?

Has anyone had really good or really bad experiences with any of these options?

Am I missing a good alternative?

Thanks!