Well late seeing this post but here's a list of my purchases and my experiences in them.
Jubilee Mk1 twin jackpots - The guys on here helped me a lot, and yes, no electric was a big plus. This was a good machine to get to grips with as you could open the front door straight up and remove the mech easily to work out what wasn't working then easily slot back in. Things like reels going slowly, handle pump not working etc, adjusting clock fins to get speed of reels correct etc.
Second was a Sega light up clone - Very easy to work on but access to mech is from the rear. Not too much a problem if you are leaving machine out somewhere but I didn't have a lot of space and the Jubilee could sit on a stand and I could remove the mech a lot quicker when it was playing up.
Third - British refurb of a German machine (the Roma, it's on this forum). This just involved me picking the locks and just playing it a lot as I was lucky in that it was all there but just gunked up.
Fourth - Sega Windsor. Not so good to get to grips with as it used electricity for solenoids on play cycles and of course electricity worries me a lot. I got there in the end but these have chrome doors and get pitted. Massively expensive to rechrome.
Fifth - Jubilee OXO (Powell's conversion). Easy to understand, it had two plays for one coin and this took some fixing, electric just used for lighting.
Sixth - Sega Continental - I'd avoid these like the plague; they are massively heavy; lot of brightware which gets pitted which is expensive to get done; even with the mech out they are like lifting a safe. The only ingenious thing about them is that the mech can be pulled forward still in the cabinet and has a swivel turntable at the bottom. I guess this explains why they are so heavy as they won't tip.
Seventh - Bally Gold Award - Nice size machine but all uses electric for coin in and out and got a sting off one; they burn out a lot (friend owns local amusement arcade in Pagham with around 20 Ballys and slowly they are dying out as he can't find replacement parts).
Eighth - Aristocrat Olympic (it's like an Arcadian mk2) - lovely machine to work on, easy to understand, electric only for lights, great starter machine. If you get a 1p one you can get the coin entry laser cut to take 20p coin, fabulous money box.
Ninth - Aristocrat Esprit - Another easy to understand machine, uses plastic reels and plastic cogs (which can wear), but it's simple and electric just for lighting.
So that's my take on the bandits I've bought and everybody on this forum has helped me with each and every purchase. I concur with the guys here: Jubilee or Aristocrat to get going. Take your time over it; don't rush in. Photos on ebay etc. can be deceptive to condition. Ask if you can view, play the machine, see if coins go in, pay out etc. Check the chrome work out. Is machine open? The times I've seen the words "we have no keys and the machine is locked but easy to drill out". Believe me, Ace locks are really hard to drill out and then you've still got to find the door opening component somehow through the drilled out hole. If the machine is open locks can easily be replaced and some locksmiths can rework a new key to fit the existing lock. Good luck with your hunt but be warned, you will end up buying more!!