Both ways of basing have their advantages and disadvantages. Some of these are mutually exclusive, some are present in both basings.
Let's start with the advantages of single bases:
- Figures are based singly. Well, obviously. This is an advantage because this means that the figures can be used for any ruleset with any basing system, using simple sabot bases. It also means that the figures can be used individually for skirmish games. As my main interest in this period and scale is Sub Roman Britain (or Early Medieval Britain), a period characterised by low inensity skirmish type fighting, this is a definite advantage.
- Looks. This might be a bit of a surprise - it certainly was for me - but singly based figures actually look good. You don't have the diorama effect you can create with multiple bases, but the single bases have their own esthetics, especially if you remain consistent in how you finish the bases.
As to disadvantages of single bases, there's just one, but it's a biggy:
- Transportation, both in game and outside of the game. In a game, it's obvious that moving 36 figures that are based individually is more work than moving 36 that are based six to a base. You can work around this to a certain degree with movement bases, but you have to be careful with how you finish your movement bases to avoid killing the visual appeal of the bases. Transporting figures safely to games is also more difficult for single based figures, as the tradition way of using magnetic sheeting under the bases is less effective with the smaller surface area of the magnets, and if you use slottabases, it's a devil to get the sheets to stick. However, for those with lots of money, rare earth magnets can help in that regard.
On to multiple bases. Advantages:
- Ease of movement and transportation. This is the big one. Whichever way you look at it, it is easier to move 6 figures glued on a stand than to move the same 6 figures based individually. The same goes for transportation - bigger bases means bigger footprint, which means greater stability or greater adhesion when using magnets.
- Looks. Using bigger bases, you can stuff more scenery on the base, effectively making the stand a mini diorama. It is easy to overdo this, however - if every stand in your army has a pool of stagnant water, two ducks and three tree stumps on it, along with enough greenery to hide an army of frogs, you are probably taking this a bit too far.
- Fixed position of figures. This is actually two advantages in one: on a multiple figure base, you can to a certain degree 'protect' certain fragile figures by putting them towards the middle of the base, thus preventing handling damage, and you can position figures in such a way that they fit nicely together &emdash try lining up a pike phalanx in single figures to see what I mean.
- Lack of flexibility. The bigger you make your bases and the more figures you put on them, the less the number of different rules systems you can use them for. If your are the kind of gamer who plays one ruleset and one ruleset only, this is actually an advantage, of course, but if you are like me, you want to use your figures for as many different rulesets as you can get your hands on (all in search of the Perfect Ruleset, of course). There is no beating the flexibility of singly based figures.
On the face of it, multiple basing seems to come up on top when looking at these advantages and disadvantages. Nevertheless, I am currently rebasing most of my 25mm Ancients to single figure bases, and more specifically slotted bases from Hetzerdog. Why? Because I found that the look of ranks upon ranks of single based figures does appeal to me, and that using single bases makes it easier to stay consistent in basing, as opposed to the multiple bases where one set were finished with static grass and painted Polyfilla, the other with two colors of flocking, and yet a third with painted parrot cage sand. With the single slotted bases, the only viable way of covering the slot is by using Polyfila, so every base will be Pollyfilla and static grass (with the odd bit of extra embellishment).
Special figures will still get their own base (e.g. Bartholomeus Sinister Grassus is based on a custom size base with a duck, his mascot), but the majority of my rank and file are being rebased to single bases.
Currently, a unit of Sub Roman Briton veterans (Late Roman Auxilia), a Sub Roman comitatus (BSG's comitatus) and a unit of pedes are on my modelling desk, on single bases awaiting the Polyfilla treatment. At the least, it keeps me busy :)