New Pick-Up Systems ?

An SM57 seems to be the industry standard for instrumental mics, while the SM58 is the vocal mic of choice.  Neither is overly expensive.
My wife bought me a Beta-57 (a little classier, more responsive, SM57).

Jim, Interesting. My wife has a "Beta-Sure" she uses for vocals, which she's had since the late 90's. I hadn't considered using a mic until now because I think I read somewhere that placement is tricky and unreliable but now I'm inspired to research the SM57 and Beta, and consider using one.

TonyKgull, This is what I remember hearing about using mics and why I never considered them. I definitely don't sit perfectly still when I play. I like to alternate between standing and sitting, tap my foot, swivel a bit (like you), switch legs occasionally, change arm position, etc. I love the idea of a mic, but I think my original gut feeling about it was right for me. So pick-up system in next guitar is probably the poison of choice

Jim, I do see your point and I acknowledge that you (and TonyKgull,) have light years more experience than me playing and performing live so I'm listening  to you guys. I guess the only way to know for sure if using a mic is for me is to actually try it out despite my reservations about it. I've been looking at SM57 reviews and pricing on-line and it seems that it's a $100 investment (excluding stand and cable) which may be well worth it. One reviewer recommended a GLS Audio mic as a cheaper option admitting it's not as good as the SM57 - but acceptable - so I may look into it as well.

Exactly the reasons why I prefer a pick-up to using a mic in a live situation. Live, moving away from or turning aside from a mic will drastically change the tone and volume of the guitar in whatever sound system is being used unless you have someone on the mixer who's listening carefully and riding the pot -- at least in my experience. And the feedback issue is real, since most mics (like the SM57/SM58, with which I have LONG experience) are designed to be placed very close to the sound source; if they're not, both tone and volume suffer greatly (which is why most singers in bands tend to 'eat' their mics)  It's less drastic an issue if you're playing solo where you're not competing with drums, bass, keyboard, other guitars, and maybe even horns, but with a full band and at any significant volume, miccing a guitar (in my opinion) will give the sound engineer all kinds of headaches.

If I were recording a guitar, yeah, a mic is the better choice to get that lovely acoustic sound, but not live.

For the same reasons as @sleigh and TonyKgull , I would be loathe to use a mic live.

I'm a self-confessed "pickup snob" - Not a fan of single UST's, although admit that some are better than others. I would rather put an expensive aftermarket pickup into a guitar of the same or lesser value, if I liked that guitars tone. Pickups have a come a long way. The K&K Pure mini is one of the most transparent pickups you can find, and its cheap. With a small pre-amp on a pedalboard (like a K&K or Fire-Eye), its a great option for producing natural tone in any acoustic guitar, from any price range. I like the versatility of the Baggs Anthem, and the natural tone of that soundboard mic is just superb in my estimation. I know some hate the Taylor Expression II system, but i dont think its too bad. Godin QII is amazing as well. 

For recording, I'm not a fan of the SM57. I owned one for a brief period and found that it coloured the natural tone of the acoustic quite a bit. You also need a decent mic pre-amp with it. I have much better success with my Zoom H5, which has built in mic pre-amps and a lot of other nifty features.

Oh, and Jim , thumbs up for "Newgrass" - I am a huge Nickel Creek fan - They were the hidden gem of the early to mid 2000's!

Jim , Yes agree that the 57's and 58's are great all rounders. If I were to buy any dynamic mic again for live it would be a 57. Can use it for pretty much anything - sounds great in front of an amp.

Chris uses a pickup most of the time, becasue he moves around a lot on stage. He is a true genius. Check this out: