What makes a good unit?

For the last couple of weeks I have been discussing with my gaming group what makes a good unit.  More specifically, what makes a unit useful to the codex that it resides in.  This is quite an important distinction.  A unit may be poor on paper but be an armies only significant threat against certain units, or it may be generally pretty useless but bring along some useful utility ability which make it useful in certain build combinations.

There are usually a lot of different choices but these can boil down to a three distinct unit types:
Scoring
Fighting
Utility


First of all we need to consider scoring units.  In 66% of all games played by the core rulebook, you will be playing for some objectives.  This means first and foremost you need to look at what troops choices, or other scoring units you can take.  Different armies have different amounts of troops choices.  Some, such as chaos marines have five troops choices, other such as grey knights only have two troops choices.  Most armies fit between these two extremes, usually towards the grey knights end in number.  Some units are primarily just scoring units and bring virtually nothing else to the table.  Some examples of these are plaguebearers in the daemon army and grots in the ork army.  These units will typically be either very cheap so you can take a lot of bodies or very tough but offer virtually nothing else apart from parking on an objective.

Fighting units are those which have been purchased to inflict and take damage.  A unit can be a fighting unit as well as a scoring unit, in fact this is quite common.  Most scoring units will be fighting units in some way or another.  The distinction between just scoring and fighting and scoring is that the fighting unit can inflict reasonable damage on other fighting units.  Most scoring units will just be able to score, and will fold in short order if charged by anything half way competent.  Tactical marines are a good example of a scoring fighting unit, being able to take a heavy weapon, special  weapon and equip their leader to have a selection of other items.

Utility units are the third and final part of the jigsaw.  These cover a myriad of different things, but it can be more or less summed up by something that doesn't inflict damage, take damage or score.  Now you may be thinking why on earth would I want to take one of these units.  The answer is often quite simple.  They allow you to influence the game in a different way.  I am including all fast moving units in this section as well as transport tanks.  A rhino is a great example of utility.  It offers no scoring ability and has just about the poorest weapon for its points value that I can think of.  Yet it is a brilliant unit because it can protect your troops, move them around and your opponent doesn't know what you have inside until you reveal it, so he has to assign it an unknown threat rating.  Other examples of utility are Eldar Farseers.  They have a fairly poor statistic line but come able to be equipped with a selection of powers which boost directly or indirectly their units, be it by allowing them to reroll to hit, wound or save.  Some people may call utility units force multipliers or support units, but the name really doesn't matter.

Having considered the different types of unit we now need to look at what makes them good.  For any unit to be considered to be a good unit, it needs to fulfil one of the following criteria.  It needs to either be powerful, cheap, survivable or flexible.  Ideally some combination of the four.  Often a unit can be cheap and powerful, such as ork boys, but they have poor armour saves.  Tactical marines on the other hand are very flexible in terms of equipment and have good saves, but are only average on power and quite expensive.

You need to weigh up the various pros and cons of each unit against what other units in your codex can do.  Taking some of the units I was discussing with a friend of mine recently as an example, we consider Ork buggies vs dethkoptas and normal nobz vs Mega armour nob units.   I was trying to convince him he would be better to take ork buggies and mega armour over dethcoptas and normal nobz units.  In the case of dethcoptas they have scouting and bikes, compared to armour ten and being cheaper on the buggies.  The buggies are around 8% cheaper with rokket launchas than the dethkoptas, and armour value tends to make the unit far more survivable than toughness and a save.  As both units are in the same codex and fighting for the same fast attack slots you can make this comparison.  The same goes for mega nobz vs regular nobz.  The mega nobz have a good armour save and come equipped with a power claw and areasonable gun with options of combi weapons.  The eavy armour nobz can take a huge selection of wargear, including invulnerable saves and feel no pain and indeed bikes to exploit the wound allocation rules.  However in terms of points the mega nob is cheaper than a regular nob if the nob just buys itself a power claw.  Once you start stacking on feel no pain, cybork bodies and eavy armour their prices rocket upwards.  You would therefore expect the regular nobs to be better, simply due to the much higher points cost per model. 

If they were in different slots or a different codex, it can be a lot more difficult to ascertain if a unit is better than another one.