Features list

Lyrics	Get rid of binders (and stress). Lyrics extracted from any MIDI or mp3, when present. Integrated word processor. Cut-and-paste from elsewhere, i.e. Internet. Insert images, i.e. scanned lead sheets. Scroll any lyrics over song's duration, with no work!
Multi-monitor	Put full-screen lyrics on a 2nd monitor or a projector; for yourself, a partner or the crowd.
Karaoke	Superb smooth scroll; useful for rehearshing, etc. Broadcast-quality graphics & effects.
CDG	High-definition CDG; unlike any other CDG playback you have seen! (also known as MP3+G or MP3-karaoke) See how it looks.
Virtual synthesizer	High-quality — top-notch reverb and chorus. GM, with GS and XG compatibility. SF2 compatible.
Search easy	Find and start playing any song in less than 3 seconds! Works for title and artist alike.
Single keys	All on-stage functions by single keystrokes.
Quickies	Play recurring songs with single key, i.e. Birthday. With keys 1 to 9
Footswitch jacks	X4 model sports 4× 6.35mm (1/4") jacks allowing up to 4 external pedals. Control playback, tempo, lyrics, looping, volume, etc. Most footswitch types supported (momentary, latching, any polarity). P1 model is a pedal with USB cable for plugging directly into the computer.
MP3	Pitch & tempo controls, separately adjustable.
Play from 1st note	Automatically skip empty space at song's beginning. Play fast.
Sysex reset	No more weird sounds because previous song messed up your synth. Automatic before each song. Supports GM, GS and XG synths.
Mixer	Can make and save changes during playback. Mute / solo settings also saved.
Multi-port	Up to 10 MIDI interfaces can be used simultaneously.
No limits	Unlimited songs, sets and songs-per-set.
Screen layout	Completely configurable. Resize panels, indicators, lyrics area, etc.
Set report	With total playing time. For each song: playing time, tempo, lyrics...
Tempo percentage	Works even with further tempo-changes within song.
MIDI pitch	All tracks at once. Everything is transposed without cutting notes.
Never wait	Songs load with no delay, no fuss.
Auto scaling	When resizing forms, their content zooms.
Resolution independence	Same appearance regardless of resolution, be it 640×480 or 1900×1200. Move between computers without formatting any lyrics. Support any screen type, including wide-screen and portrait monitors.
Visual themes	Many quality themes provided: Dark, light, seasonal, etc. Or create your own themes with the powerful Theme editor.

Want more?   Here we go...

Insert or add special-requests at will.

Pre-select next song (or set) while current song plays.
Change set order on-the-fly (just move the cursor bar).

3-bars pre-count for markers to see them coming.
Useful to identify cue-points for start of verses, solo, ending — mostly for non-karaoke songs.

Always proper sounds, levels, etc. No matter if pausing, skipping forward, etc.
Even jumping mid-way in long sustained notes sounds these correctly.

Lock transposition for all songs until you reset it; a life-saver when your throat begs for relief.

Easily modify the type of reverb and chorus for individual songs (Hall, room, etc).
You can also specify the default reverb and chorus type for all songs.

Specify MIDI channels that will pass through your synth,
allowing your songs to control external effects like reverb, guitar processor,
harmoniser, light dimmer packs, etc, without a 2nd MIDI interface.

Setup allows muting selected MIDI channels of specific devices.

Panic key to stop and rewind the song; also resets your synth correctly.

Customizable RESET.MID and CONFIG.MID files, to send extra sysex and MIDI commands.
  CONFIG.MID sent once at program start.
  RESET.MID sent before every song played.

Integrated song / set management; i.e. renaming a song automatically updates
all your sets to reference that new name.

Vast majority of lyrics formats are supported automatically.
Cleans up auto-extracted lyrics by eliminating spam in Title, Author and Lyrics.
Supports foreign language characters.

ShowPlay is fast, regardless of 50 or 10 000 songs in list.

Convenient mouse features for laptops, especially for trackpoint and touchpad:

• Drag forms by any empty area.
• Maximize with double-click on any empty area.
• Close forms with right-click on any empty area.
  (much easier than aiming for the small X in upper-right corner)

Songs are "striked out" when played; it's easy to see which you already did.

At the end of a good gig, ShowPlay can make a set out of the songs you played.

Select display language on-the-fly. English and French built-in.

 And a whole lot more.
 The tutorial also contains information.