So is it gonna block OTA's?
I believe it does indeed block OTAs.
This is basically a completely new OS built using the source code from Motorola with changes (the kernel is certainly recompiled with many changes).
I don't think they have recompiled the system apps, but they do wipe the /system directory and bring in a new one.
Basically, if you install this you are going to get your updates in the future from sholes.info or you will revert back to standard OS and get OTA updates.
If one is not comfortable with having their Droid rooted, with overclocking, or with someone other than Motorola building the kernel and providing updates then they should probably not install this app.
I am comfortable with it, and recommend it ... I personally will wait to install this until they have the 2.0.0 version of the ROM as I am running their 1.2 ROM now with their 1000 MHz overclocking kernel installed and I don't want to lose the 1000 MHz kernel to the older one from 1.2.
But as soon as they release the new ROM then I am all over this. For anyone who thinks that $5 is too much this app ... seriously ???? For the price of a Big Mac and Fries, you can get Wireless Tethering, Root, SPRecovery and all future updates.