The following is all from 2012

Basic Wireless-N  (802.11n) routers used the 2.4 MHz band
and 20MHz wide channels width within that band.; resulting in 150 Mbps throughput.

It allows additional features to improve performance:
However this only works if the receiving device, computer, Internet TV, ...
also has compatible enhanced 802.11n features.
   MIMO (Multiple Input, Multiple Output) uses 2 input and 2 output antennas
for increased range (2x) and throughput.
  
Dual band routers transmit on 2.4 and 5.0 GHz. The 5 GHz band can avoid interference.
   Many cordless phones, microwave ovens, baby monitors, garage door openers,
   and other wireless electronics also use this frequency. 
    (Cordless phones can use 900 MHz, 1.9, 2.4 and 5.8 GHz )
    
 Wide channels: The n spec also allows for wider channels.
 40MHz (300 Mbps), 60 MHz (450 Mbps) and 80MHz (600Mbps).
 In order to have 40 Mhz channels, you need two radios and at least 2 antennas on both ends.

2012 reviews
                                                     cnet 
Netgear N600 Wireless Dual Band Router WNDR3400 $90     4
Netgear WNDR3700 RangeMax Dual Band Wireless-N  $140    3.5
Apple Airport Express  (2012)        150Mbs       $99    3.5
  (Has AirPlay - Audio output)
Apple Airport Extreme              270Mbs       $169
Vizio XWR100 dual-band wireless router          $60-80  4
Linksys E2000 Advanced Wireless-N Router       n $85    4    (fastest per cnet) 
Linksys E3000 Advanced Wireless-N Router       y $85    3.5 (NAS slow)
Linksys WRT610N Simultaneous Dual-N Band        $140    3.5
Netgear WNDR3700 RangeMax Dual Band Wireless-N Gigabit Router (Premium Edition)
Belkin N600 HD                                            (USB 12 Mbps transfer rate)
Single Band
Belkin N+ Wireless Router                        $85     4
D-Link DIR-655 Xtreme N Gigabit Router           $85     3.5
Cisco Valet Plus                                 $100    4
Cisco Aironet 1140 Series Access Point         300Mbps  $648