Something that may work for scoring is You Rock Guitar
(YRG) and they are cheap.
I used to have a Fender Start driving an Axon AX50 USB. While it was fast and handled bends really
well, not having the smoothest playing technique meant I kept generating too many false notes, triggered by just touching the string before actually picking or strumming. However, I was impressed by its responsiveness compared to the delays I remember hearing years before on a friends Roland MIDI pickup.
We had only got it for possibly putting in incidental sample sounds, so given the learning curve that would be required to be able to use it consistently verses the amount of times we would, we sold them.
Since the YRG was so cheap (<US$100 at the time), I bought one to just muck around on. It has plastic coated string-wires for plucking/picking/strumming and a separate plastic moulded fretboard with ridges for strings. The fretboard doesn't allow bending, for which the whammy bar is to be used, and the string-wires feel a bit like fence-wire.
It is designed to be used for real direct MIDI or MIDI over USB work, and includes a range of samples on board and some patterns to which you can play. It even has a 'safe' note filter, that only plays the pentatonic notes for the key of the pattern.
However, its real advantage is that it can be configured to not trigger on fret touches, but only on the string-wire hits. Conversely, it can be used polyphonic so that ANY fret touched will play a note, even those on the same string, without hitting the string-wires. As with the Axon, you can have separate MIDI channels for fret ranges and each string.
This makes it have almost no learning curve for putting clean notes into scores. On first use, my wife had no problem playing chords with the YRG driving EWQL Pianos to produce very passable Steinway piano. Though she thought the string-wires felt strange, she thought that it wouldn't take long for her to play proficiently.
As I can now sort of play lead, I would not hesitate to use it for any incidental instrument samples where we don't have a long-term need to buy the real thing. However, the lack of real bending precludes decent expressive driving of solo string samples.
Certainly, given the flexibility of usage, and that lack of real bending is not an impediment for scoring, I would think that the YRG is probably the easiest way to MIDI score if you are a guitarist. And you don't have to think which guitar you want to risk drilling holes into for securely mounting the pickups for any other MIDI system, though I did find a way to use existing Strat screw-holes with the Duncan pickup for the Axon.
If you do get one, I would suggest slightly loosening the string-wires (about a quarter turn) so they feel a bit more normal.