Maybe i can clear this up. I now have both Gen7 and Gen5.0 Tarkan dual SD TeraPods working perfectly with RB. The Gen7 problems were overcome when the RB upgrades were made to the latest ClassicRB versions on the website. I could not get a stable TeraPod Sd build from the version on Tarkan's site. The Gen5.0 works straight off the latest stable build on the site.
There is no track limit to the number of songs, so far, except for the physical limit of the memory when using RB. I currently have more than 150,000 files on the Gen7, and expect to have that many on the Gen5 by tomorrow. This is about 660gb of mp3, aac, and flac files. The track limit of about 56K songs is true for the Apple OS, regardless of the Generation. I have run into problems with some Chinese Gen5 boards when using the Apple OS - and the databases become corrupt below the 56k limit. I also had a lot of playback stability issues above 600gb using a 32ram logicboard (so I quit using them). I've tested the mini with a 256gb SD card, and it wasn't stable with that many songs using the Apple OS I stay below 128gb with the mini mod, since I run the native OS on the minis.
My Gen7 has a 2000mAh battery and will run for at least 3 days straight without recharging. I haven't stress tested the Gen5, which has a 1300mAh battery. I've not had any playback issues, yet. On my most recent business trip to Europe, my mSata Terapod Gen5.5 froze, restarted to the sad face, and needed to be reset. I've yet to have this happen with the SD TeraPods.
I own every type of iPod, with every available memory configuration. I, personally, can't tell the difference between mSata and SD versions. I believe the Gen5 sounds better than the Gen7, which soumds better than the mini. But I have old ears and I listen to old rock music. My goto TeraPod is a Gen5.5 64ram Samsung mSata 840, but i must admit - the SD TeraPod is more energy efficient, and more stable. Nevertheless, you can't beat the price of an mSata compared to the other storage options.
As far as loading goes, sometimes I load through RB, sometimes through the Apple OS under the dual boot (Gen5 or 5.5). I've found loading though the OS is faster. If I am worried about the battery, I load with a dual-firewire cable. When loading to an mSata, I keep the initial loads to around 30gb at a time to avoid overheating. On the dual SD builds, I've loaded 150gb in a single run.
My last three builds have been Gen5s. Once you get RB loaded, you can pull the mSata or the dual SD from the iPod and load all the music externally 5-10x faster than while in the iPod.