'planar' vs. 'boxes'

That's a very broad question. All I can do for you is give you some opinions and facts. But the first thing I say is: listen for yourself!!!!!! If you find a speaker, no matter what kind of speaker it is, that you like (and can afford) buy it. One big difference between conventional (box) speakers and panelspeakers is that the latter is bi-directional, which means they are much more sensitive for room-placement. Also, most panelspeakers have a low sensitivity/high capacitance, which means they are not suited to low-output amps and/or amps that cannot deal with low capacities. On the plusside however, panelspeakers are capable of breathtaking soundstaging and treble-performance. Onfortunately, for an extended low-end performance large panels are needed. Maybe your best bet is to go for a hybrid system, something like a Martin-Logan, or maybe Quad ESL-63 with matching subwoofers.

Excellent answer by Michiel, you should read it twice slowly. Objections to planars are the lack of bass and the size of the image, perhaps you like a guitar that's nine feet wide, but it's not very realistic. From planars, this listener has switched entirely to point source dome tweeters and mids, the computer-designed speaker revolution begun in the mid 80's has paid off fifteen years later in some absolutely stunningly transparent designs, while planars have fallen far behind. As Michiel said, "Listen for yourself".

If you want a no risk hands-on experience with planars order the little $500.00 mail order Magnepan MMG's. You get to try them for 60 days. I used to build box speakers as a hobby but now own full range electrostats (SoundLabs). Planars have a much easier to deal with radiation pattern. You see, if the direct sound and the reveberant field have a different tonal balance, you eventually get listener's fatigue (headache). Conventional 2-ways, for example, have omni dispersion in the bass, narrowing considerably in the midrange as we approach the crossover point due to woofer beaming. Then hemispherical on the tweeter's side of the crossover point, progressively narrowing with increasing frequency as tweeter beaming sets in. In this case the reveberant field cannot possibly have the same tonal balance as the direct sound, no matter what your room treatment or equalization. With a planar, you have a figure-8 pattern in the bass and (depending on type) either severe beaming treble beaming (flat panel), essentially spherical treble dispersion (narrow ribbon tweeter) or figure-8 dispersion all the way up (curved panel). So avoid a flat panel sans ribbon tweet - i.e. old Acoustats. Since high frequencies are much easier to absorb than low ones, some foam behind a narrow, ribbon-type tweet speaker (Magneplanars) can correct the tonal balance in the reverberant field, if needed. Curved electrostats (Martin-Logan, SoundLab) are the best approximations. Line source approximations give a wider "sweet spot" than point source approximations, and planars are inherently line source approximations (as are big Genesis panels and Pipedreams). Okay so much for theory. Order the baby Maggies, they may sound a little harsh at first but let them break in (48 hours playing time), give them a touch of bass on the tone control (if you have one), and you will know for yourself.