With the sgh-i777, cwm recovery is a part of the kernel. The step in the guide that instructs you how to install the kernel, is where cwm recovery is installed. So the real choice is which kernel to install.
---------- Post added at 10:53 AM ---------- Previous post was at 10:47 AM ----------
Since your phone is already rooted, you follow the steps under "install the kernel"
---------- Post added at 11:04 AM ---------- Previous post was at 10:53 AM ----------
Overview of steps from stock to custom recovery for the i777:
Framaroot <-- tool to establish root-access to the device
Mobile Odin Lite <-- tool that uses root-access to install...
Custom Kernel <-- a custom kernel (there are many available) installed primarily to provide cwm recovery, but are also commonly used to:
-provide additional functionality to the existing ROM
-backup your ROM install
-install a different ROM
-install a different kernel
-flash cleanup scripts
-and many many other things
The ROMs are usually packaged with their own kernels, so the kernel used above only remains in place until another ROM is flashed, which will overwrite the existing recovery with one specifically designed for the ROM flashed.
I strongly recommend using cooks rom-wipe-script inbetween all roms (even similar ROM's), to avoid issues from flashing one to another. Titanium Backup Pro (setup correctly) is your best friend when it comes to transferring all necessary data and app favorites.
not properly wiping in between roms is the seed for trouble, whose effects are most often incorrectly blamed on Roms or Kernels.