This technique when power limited or VIPs onboard or if it's a tricky to judge approach such as a confined area or a raised pad.
Variable speed: you establish your approach angle and decrease your speed gradually in proportion with your distance to the pad, all the way working the collective to stay on the glide slope. Finish with very gentle leveling off. [This allows you to climb on the back of power curve super progressively]
This technique, or similar most other times: (my advice is to do it not pointing at the pad, leave a 90deg turn-on for the latter stages, that way your judgement of the decel is not critical, you just decel, and turn the last 90deg when you have the crafts speed at a manageable pace)
Constant speed: establish your approach angle and keep your speed 60 knots or above as long as practicable (collective hardly requires any work because all things remain equal) finish with a solid flare and leveling off. [The later part requires you to climb on the back of power curve very quickly]
passenger comfort, risk profile, landing situation, weather, type of aircraft. what factors come into play?[/QUOTE]
When you have hours under the belt, you can blend the techniques seamlessly, varying approach style according to the situation.