For ages I've been whingeing on about the difficulty of reading draw weights accurately.
Now I'm under no illusion at digital is necessarily more accurate, but when I was mooching around on E-bay one lunchtime (as you do) I spotted some 50 kg digital hanging scales luggage scales at a silly low price. I got 'em for £5.30 including postage! Can't lose at that price, they arrived this morning and look very nice, good back lit display (the back light has switched off in the pic)
It can be set to read in pounds and it's even got a smiley face, what more can I want?
I'll have to make/modify the handle to hook onto the bow string, but one advantage will be the lack of mechanical backlash and absence of elongation which you get in a spring type scale. It will be handy to see how it agrees with my other scale.
Only going up to 110# will limit it a bit for warbows, but it's great for the general draw weights and will certainly cover anything I can draw.
If you look for one, watch out as some only go up to 40kg.