The current situation for resto druids isn't very good right now, compared to where they used to be. They are being outmatched by paladins by far and they are on equal terms with shamans and priests. The difference is that resto druids bring nothing to the raid that another healer can't bring. The only thing that is unique about resto druids is of course their HoTs, but Dragon Soul has a lot of instantaneous damage and people are getting topped before the HoTs tick now with the damage reduction buff in Dragon Soul. The only thing resto druids bring is a 3 minute raid cooldown (Tranquility), which is worse than Divine Hymn, where the only difference is the cooldown (8 minute on Divine Hymn for Holy Priests). I'm not saying it's bad, but it could be better since druids only bring healing to a raid now.
The fights where Resto Druids excel at are Morchok, Warlord Zon'ozz and Spine of Deathwing (debuff-"whoring"). The reason behind this is it's simply those fights where our HoTs are more useful and get to heal away. On Morchok there is a lot of damage that isn't random and you can easily pre-HoT and get into good position for the mace proc and if you are soaking the black goo you get a lot of healing via that as well. On Warlord you can have HoTs rolling on all targets with debuffs if your guild does not dispell them, which will make it a lot easier for the other healers. Spine of Deathwing is similar to Warlord, where you keep your HoTs rolling on the debuffed targets and you use cooldowns during AoE explosions or rolls.
The situation was different from the early state Dragon Soul where the debuff didn't exist and people didn't top damaged players as fast as now, that's why druids are on the downside right now. Hopefully it will change in Cataclysm and we get some amazing utilization abilities such as Symbiosis and our talent tree can be swapped around to cater every fight in a different way, and I can see many talents being useful in certain situations.
Healing as a Resto Druid can be stressful the first time you experience the encounter. The secret behind a good Resto Druid is
knowing the fights, meaning you know where and when the damage is going to strike and you have your HoTs and position set up. When you've done the boss once or twice it gets a lot more comfortable and it's just like any other class, just that Druids specialize on HoTs more than smashing buttons and reacting to people's health dropping. You need to have an understanding of how you deal with the encounter and have a foresight of where the damage is being dealt. This is why I hate fights such as Madness of Deathwing (mainly the smash from the tentacle, it's random and stupid as hell). The most stressful fight I've encountered so far is Sinestra. Keeping Harmony up is neither hard nor stressful. Keep in mind that your Swiftmend applies Harmony and it has a 15 second cooldown, so basically if you keep your Swiftmend on cooldown you only need to throw in a Nourish, Regrowth or HT 6-7 seconds after you've Swiftmended someone. I know you don't keep Swiftmend on cooldown on certain fights because you need to base that decision on if Efflorescence is going to hit multiple people.
Sorry for the long post, but this is how I feel the current situation is. I don't have time to read through my post right now since I'm kind of in a rush.
Resto druids are awesome by the way!