I've recently got back into playing after a 10 year break. Back then I was learning from tablature online displayed in monospaced font, the quality of which varied from nothing like the music to pretty good.
Today, I find not a lot has changed, except the sites where I used to go to find tablature are now charging for the same material.
I'd like to pay for quality transcription of music (like the official music books) but available online or in an app.
I know how you feel. I studied piano as a child but I learned a bit of guitar by myself. I often find myself looking up tabs and then switch to learning by ear because not only they are wrong but also "stupid" (as in, use weird and difficult hand positions which don't make any sense). And yeah, pretty much all the main websites try to force you into paying for some service you don't want or need with popups and stuff that you would only see on a torrent search engine.
I think the main problem is that most people use tablets/phones to look up songs and so they most likely use Apps or learn from YouTube videos. I find the latter option quite time inefficient.
I have been thinking about implementing a github-style website for tabs but it seems that the interest for tab sites is slowly fading away.
I haven't played for about 10 years as well, and I fondly remember the ascii tabs.
But maybe you never found the alternative, which was a program that was basically a midi player that display all chords and notes in timed bars and play the music, with all the instruments split up.
You always knew the quality was good, since you could have the computer play the track to check it out before practising.
I don't remember what program I used back then, but this looks like a spiritual descendant, though I am not recommending anything:
For an open source multi-track tab player/composer, check out TuxGuitar. It reads several popular tab formats. Sound depends on underlying MIDI system, may require a little futzing to get going. Written in Java, runs on Windows/Linux/OSX.
Checkout songsterr: http://songsterr.com there's others similar, but I prefer this one. Bonus points, if you open the web inspector and view a song, you can get the http request that downloads the .gp4/5 file and download the file for yourself.
And no, I'm not ashamed to do this; I was one of the lots of guys that submitted gp3 in early 2000's by manually transcribing them; later these community-generated tabs were takend down (DMCA I guess) but I was dumbfounded when I learned that some companies were selling access to the tabs.
I would suggest you check out Troy Grady [1]. I've been playing the guitar on-and-off for 33 years, and most of the 'off' has been because I've reached a hard limit for picking speed; my left hand has always been pretty good, but right hand and high-speed synchronisation has always been a problem, and I never fixed it, just got frustrated, stopped and then started again. While I teach for a living now, it wasn't until I saw what Troy Grady has analysed and offered that I started practicing properly again after years of neglect. While I have a LOT of work to do to get my right hand sorted, after a few months I'm starting to see glimpses of improvements, and being able to pick well.
If you're of my age (I'm similar age to Troy Grady, 45), then the free cracking the code videos on YouTube are a good watch anyway - entertaining as well as the story of playing guitar that I largely paralleled (but never found the solution that he did, alas, until now).
Not sure what's out there for pop music, but for jazz iRealPro is indispensable. Thousands of chord charts for jazz standards are available on their forums (which is linked within the app) and the it can do playback, including the ability to silence particular instruments.
This probably varies by genre, but I've found that if you add "pdf" to your search, you'll often find high-quality handwritten sheet music, sometimes with tablature. I've also found scans of out-of-print music books.
It's free, it's like Wikipedia in that anyone can edit it (so crappy transcriptions get replaced eventually by better ones), it even plays the song for you. The only bad thing is that it uses Flash.
Today, I find not a lot has changed, except the sites where I used to go to find tablature are now charging for the same material.
I'd like to pay for quality transcription of music (like the official music books) but available online or in an app.