I have had dogs all my life. All kinds of breeds, some altered and some not. I can honestly say I have NEVER seen a difference in any behaviors - good or bad - after I've had a dog altered.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar - Texas Blue Lacy
Funyon, Ashe, Soot - Barn Cats
Scooter /1/2 Arabian, Shadow, Katie / APHA