Solid Block Activated Carbon (SBAC):
    Activated carbon is the primary raw material in solid carbon
    block filters; but instead of carbon granules comprising the
    filtration medium, the carbon has been specially treated,
    compressed, and bonded to form a uniform matrix.  The
    effective pore size can be very small (0.5 - 1 micron). 
    SBAC, like all filter cartridges, eventually become plugged or
    saturated by contaminants and must be changed according
    to manufacturer's specifications.  Depending on the
    manufacturer, the filters can be designed to better reduce
    specific contaminants like arsenic, MTBE, etc. (an example)

The advantages of SBAC filters include:
Provide a larger surface area for adsorption to take place
    than Granular Activated Carbon (GAC) filters for better
    contaminant reduction. 
Provide a longer contact time with the activated carbon for
    more complete contaminant reduction.
Provide a small pore size to physically trap particulates. If 
    the pore size is small enough, around 0.5 micron or smaller,
    bacteria that become trapped in the pores do not have
    enough room to multiply, eliminating a problem common to
    GAC filters. 
Completely eliminate the channeling and dumping problems
    associated with GAC filters.
SBAC filters are useful in emergency situations where water
    pressure and electricity might be lost.  They do not require
    electricity to be completely effective, and water can even be
    siphoned through them.
SBAC filters do not waste water like reverse osmosis.
Many dissolved minerals are not removed by activated
    carbon.  In the case of calcium, magnesium, potassium, and
    other beneficial minerals, the taste of the water can be
    improved and some (usually small) nutrient value can be
    gained from the water.
Simple, economical maintenance.  Typically an inexpensive
     filter cartridge needs to be changed every few months to a
     year, depending on water use and the manufacturer's
     recommendation.

This combination of features provides the potential for
    greater adsorption of many different chemicals (pesticides,
    herbicides, chlorine, chlorine byproducts, etc.) and greater
    particulate filtration of parasitic cysts, asbestos, etc. than
    many other purification process available. By using other
    specialized materials along with specially prepared
    activated carbon, customized SBAC filters can be produced
    for specific applications or to achieve greater capacity
    ratings for certain contaminants like lead, mercury, arsenic,
    etc.

The disadvantages of SBAC filters include:
SBAC filters, like all activated carbon filters, do not naturally
    reduce the levels of soluble salts (including nitrates), fluoride,
    and some other potentially harmful minerals like arsenic
    (unless specially designed) and cadmium.  If these
    contaminants are present in your water, reverse osmosis
    would usually be the most economical alternative followed by
    distillation.
It is important to note, particularly when using counter-top and
    faucet-mount carbon filtration systems, that hot water
    should NEVER be run through a carbon filter. I have
    seen warnings about possible damage to the filter from hot
    water. Perhaps more importantly, hot water will tend to
    release trapped contaminants into the water flow potentially
    making the water coming out of the filter more contaminated
    than the water going in. 
As SBAC filters remove contaminants from the water they
    gradually lose effectiveness until they are no longer able to
    adsorb the contaminants.  There is no easy way to determine
    when a filter is nearing the end of its effective life except that
    the 'filtered' water eventually begins to taste and smell like
    the unfiltered water.  The manufacturer's guidelines for
    changing filter cartridges should always be followed.

You might want to check  NSF International to see if the SBAC filtration system you are interested in purchasing is certified.

An example of a certified list of contaminants significantly reduced by a high-end SBAC filtration system (** at 200 percent of capacity - that's after filtering twice the rated volume of the filter*):
 For Standard 042 - aesthetic
   Chlorine Reduction, Class I
    (actual chlorine reduction 99.9%)
   Particulate Reduction, Class I
    (actual particulate reduction down to 0.5 micron)
   Chloramine Reduction
    (actual chloramine reduction greater than 96%)
   Taste and Odor Reduction
 For Standard 053 - contaminants of health concern and measured percent reduction
   Asbestos Reduction >99%
   Chlordane Reduction >99.8%
   Cyst Reduction 99.9%
   Lead Reduction >98%
   Mercury Reduction >99.3% (pH 8.5) >91.4 (pH 6.5)
   MTBE Reduction 96.6%
   PCB Reduction >98%
   Toxaphene Reduction >93%
   TTHM Reduction (Trihalomethanes) >99.8%
   Turbidity Reduction >99%
   VOC Reduction (volatile organic chemical) Reduction - you will see a
   long list of specific VOCs (individual percent reduction for the various
   VOCs can be found on the product certification sheet below, but
   most are 98-99% or more).
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A few SBAC filtration systems have been certified for arsenic reduction: