Aerial Insectivores vs. Foliage Gleaners

Bats are typically classified as either "aerial insectivores" or "foliage gleaners."Most bats fall under the aerial insectivore classification. They use echolocation, also referred to as biosonar, to not only hunt and capture food (or to detect immobile food if they are foliage gleaners), but also to navigate their environment. They tend to have longer, narrower wings for foraging over long distances in little time. They travel far in one night and can either be loyal to an area or move to another location with another roosting area.

Foliage gleaners on the other hand, rather than detect the movement of prey, they use echolocation to map their environment in detail as well as listen for insect calls in order to locate immobile insects, fruits, and/or flowers.  A few bats with this foraging style actually don't use echolocation, but instead use keen eyesight to locate food.  Their wings are broad, giving them high maneuverability and allowing them to hover.  The wings also decrease their ability to fly long distances, so they tend to be loyal to an area where their food is abundant.  They typically have long, highly manueverable ears to hone in on specific locations.  The insect-hunters, because the prey is so large for them, generally have to go to a nearby roost where they pick off the extremities before ingesting the good parts.

http://www.batcon.org/index.php/media-and-info/bats-archives.html?task=viewArticle&magArticleID=334

Microbats (suborder Microchiroptera)

*see also "Differences Between Suborders of Bats" for very basic information

Microbats are insectivorous, mostly eating insects with the major exception of the ghost bat from Australia, which has been known to eat frogs, birds, lizards and mammals even including small bats.  They range from 3-150 grams and typically have wingspans around 25cm.  They are nocturnal and use echolocation and poor eyesight to locate prey.  Only 2 species of bats have potentially audible echolocation frequencies, but most sounds we can hear bats make are either social chatter, communition with young, and alarm calls.  Microbats have been recorded to find prey as efficiently as one insect every three seconds with their excellent echolocation.

Microbats fly at a range of speeds with varying maneuverability, from slow, fluttery, and controlled to fast and much less easily controlled.  Microbats typically catch and eat their prey while in the air, but they can also "glean" insects that are not in the air and pluck them off surfaces or out of webs.  They do this either by flying slowly and identifying the insect on the plant with echolocation or by perching nearby and simply listening to the movement of the insects.

Microbats like to roost in caves, tree hollows, and many other small crevices including manmade crevices typically in areas where their natural habitat is small or far away (although I believe they may sometimes prefer manmade structures, especially heated structures, for better warmth and a reliable shelter).  They roost upside down because they developed wings at the expense of their ability to stand, developing specialized tendons in their feet by which they can hang effortlessly.  They can also hang from their thumbs when they need to give birth or drop waste.
http://www.derm.qld.gov.au/wildlife-ecosystems/wildlife/az_of_animals/micro_bats_the_insect_terminators/

Difference Between Two Suborders of Bats

All bats fall under the order Chiroptera into one of two suborders: Megachiroptera and Microchiroptera (or megabats and microbats).  The names do not refer to size.  All bats of both suborders can be any range of sizes anywhere from the size of a small dog with a 2 meter wingspan wieghing 1.5 kilograms to the size of a bee weighing 2 grams.  All megabats reside in the "old world" (before columbus) in tropics and subtropics while microbats can be found all around the world.

Megabats feed almost exclusively on flowers and fruit.  They have large eyes and typically dog-like faces.  Megabats rely on smell and vision to find food and do not use echolocation with the exception of the Egyptian fruit bat, which does incorporate a form of echolocation.

Microbats have more varied tastes including: insects, fruit, pollen, nectar, fish, frogs, blood, and even other bats.  They have small eyes and often elaborate facial construction.  All microbats use echolocation to detect their prey.
http://www.bats.org.uk/pages/bats_of_the_world.html