The isida is a valuable asset to any team battle, both short and long. good use involves: 1. going to front line with buddy 2. staying behind lines to heal long range defenders 3. any time you have a power-up Isida is valuable, but is also in great danger. the enemy will often time kill the isida first. to prevent from the one-hit-kill power of the shaft, you need something sturdy. to be effective on the field of battle, you need something fast. the viking fits this description of the optimal hull for isida very well. make sure to regularly upgrade the viking in battle, and you will continue to be sturdy enough to take the hit against any shaft. my point, if you had the choice to upgrade the isida or the viking, upgrade the viking. you will last longer to heal more allies, and you will get to them faster too. however, don't neglect to upgrade the isida sometimes though. if the viking is m1 while the isida is m0, don't get viking m2 before getting isida m1. it is much cheaper to have an overall balance than to specialize in one thing.