Are these recommended for PC?

I see tons of DLs for them. I currently don't notice any gamebreaking or annoying bugs.

I see some people have random issues from reading comments, but I am sure they are the exception.

My game is heavily modded. Is it recommended for games with lots of armor/item/graphical mods?

What's not to like? They fix numerous (literally hundreds, if not thousands of) vanilla bugs and don't do anything bad.

The Unofficial patches are highly recommended to fix vanilla game issues, whether you have mods or not.

The Unofficial patches should be considered required on all mod setups (barring TCs like Nehrim, none of which exist for Skyrim yet).

They are essential. Just make sure to sort with BOSS so they're at the top of the load order and won't effect the rest of your mods.

And just to prove how REQUIRED they are for me: when I bought Dawnguard and Hearthfire, I actually disabled dawnguard.esm and hearthfires.esm until all 3 of the unofficial patches saw stable releases on the Steam Workshop before I actually start playing the DLCs.

And they only get better with age too

The thing about bugs is that you don't really care about them until you happen upon one. Some may just be immersion breaking (e.g. a free flowing pot of flowers), others can be annoying (e.g. not being able to use smithing to upgrade a certain item) or even outright game breaking (malfunctioning quest). Some may be very difficult to fix after the damage is done. Better to get as many bugs fixed, before they mess with your game.

How do you sort with BOSS? The download is no longer available.

http://code.google.com/p/better-oblivion-sorting-software/downloads/list

The TESNexus page for it links to it's google page. They don't actually upload it there.

Or just use the link Frihyland posted