LT Spice Comparator Question
Yeah that should be fairly easy:

Step 1) Create a B-source

Step 2) Set the B-source value to an expression like this:

V=IF(V(node)&gt;1,1,2)


where the first term is the expression A>B or whatever, the second term is the voltage if true, and the third term is the voltage if false. (I think I have my logic right) 

You can do a lot of other algebraic expressions with B-sources, including laplace transfer functions.  Use A==B and keep in mind that if you do this V(node)==1 you'll never see this happen in a normal simulation so you'll need to if statements (A>1.1)&amp;(B&lt;1.0) so you capture a range of voltages or a rounding function.

OR 

There are some digital devices:

From LT spice wiki:


  Documented directly in Help:
      Buf (aka Buf1 Inv)
      AND
      OR
      XOR – when more than two inputs are present, uses the correct definition of true if one and only one input is true, rather than the more common incorrect definition of true if an odd number of inputs > are true (which should be called an ODD/NODD gate rather than an XOR/XNOR gate).
      Schmitt (aka SchmittBuf SchmittInv DifSchmitt DiffSchmittBuf iffSchmittInv)
      Dflop (CLR takes precedence over PRE, also a start up state may be set – see SRflop)
      Varistor
      Modulator (aka Modulate Modulate2)  


which I've never used, but they are there.