Installing just Haxchi is perfectly safe and will give you simple channel access to other homebrew programs without the need of the browser exploit anymore.
Installing CBHC though is FAR, FAR more dangerous but will allow coldboot into patched menu/homebrew, read this for more information:
Changes to Haxchi:
-use same iosu patcher for both haxchi and cbhc to allow haxchi to benefit from it
-added new config option to haxchi, "sysmenu" which will relaunch you into the system menu with signature, region patches and everything else that cbhc patches
Changes to CBHC and Haxchi:
-small logic correction in the iosu patcher