Small Fire Stream, advantages is that it requires no seals so it can be used in combat with quick succession and counter a blitz attack, the heat of the technique can render your opponent unable to combat you forcing them to momentarily retreat and relocate giving you the advantage of pursuing them in their weakened condition, or giving you an opening while they are dazed momentarily. Disadvantages is that it is a small short flame so it must be fired whistle the opponent is in front of you, it isn't a long distance technique so you must be within range and that requires a good setup, like a technique used to distract opponents such as other elemental techniques or shadow clones.
Great Fireball technique, my favorite technique is the Great Fireball technique, I see myself using this technique more times than the others cause of the advantages stated below, its advantages is that it is a technique that is powerful enough to incinerate the enemy, definitely a useful jutsu for finishing blows, distractions, lighting forest fires etc. It has two variations so it can be used in various ways to benefit the user, short range or mid range. Disadvantages is that it requires the use of hand seals and can be countered by a skilled opponent when either performing the technique or after the technique is released, weak against the water style.
Wall of Flames, my least favorite attack because it is defensive and its main purpose in my opinion is distractions and to flee mostly, it isn't a projectile and isn't the best of the lot . Advantages is that it can be used defensively to incinerate oncoming projectile attacks and provide a distraction to flee if not in a condition to fight or are surrounded by enemy ninja and are forced to retreat using the wall of flames as cover, it can be used in conjunction with another technique to fire through the wall as a surprise attack and can be used with a wind technique as a combo jutsu. Disadvantages are that you need a ligher, time to grab the lighter in the midst of battle when every bit of time is valuable can be difficult. Disadvantages, it is weak against water and you lose a lighter..
Running Fire, advantages is that its form can be manipulated and take various different forms that give an advantage to the user and can use whichever variant he/she deems appropriate in battle. It can be used in conjunction with wind techniques to enhance the attack and make it stronger into a B rank technique, a massive inferno of flames directed at your opponent can be used to attack, counter or distract your opponent. Disadvantages, water style techniques can overpower the technique, the combo with wind style requires more time and the opponent can strike.
Dragon Fire Technique, advantages is that it can capture an opponent and release a large fire technique in the form of a dragon, a direct attack from this will surely do considerable damage to your opponent. Disadvantages are that it requires hand seals in which the opponent can counter, it requires prep time to prepare a thread or line to connect to the opponent and fire upon them, it also leaves your vulnerable to attack from another enemy whistle you are focusing on the wires/lines and technique.
All the techniques above can be used as finishin blows, distractions, counters and means of escape. Incinerating the enemy is its biggest pro and its con is that it is vulnerable to the water style. Most of these techniques are meant for combat but can also be used for things outdoors on missions.