GG, I've had several different bikes from the late sixties and early/mid 70's growing up and today own several different models. I must admit - I don't like any two stroke more than my CB500 Four or my TX650 Yamaha. Your choice depends on just how and why you're going to ride it. I'm 5' 11" and a muscular 240 and here is how I sum them up -
1) R5,BC and RD350 Yamahas - great little bikes. Way too small for the average 200 lb fellow - it looks like a minibike under me.
2) GT380 - a refined and very comfortable little bike - feels larger than the Yam, but slower - it doesn't like those pounds and both the Yam and Honda 350's will beat it.
3) GT550 - my absolute all-time favorite Suk. It's heavy, but very streetable. It makes about the same power as the CB500 Four and without the sound - you'd think it was a four stroke - Suzuki did a great job of tuning these for torque and smoothness. Just don't look for any power bands - I've had two of them and never found one:)
4) Kaw H1 500 - these are a blast to drive. I really like the 500's better than the H2's. I currently have 5, but I've restored 5 H2's and 5 H1's. The 500 had the largest "port area to cylinder ratio" of any production motorcycle back in 1969. There is nothing that howls and hits like the 500's. Yes, the H2 has more low-end power and is easier around town - but if it's "rush and powerbands" you want - the Mach III is the holy grail. They are noisy, they love gas, they are less forgiving down low than anything you've ever riden. - you'll have to pick your gears - but at 5,500 rpm to 9,000 there is no better music than three carbs sucking mass quantities of air and the odd, three pipes puffing smoke and winding up like a jet engine. Any 500 in good shape will start pulling the front off the ground at 5,500. For a "perfect" streetable 500 - get the 1976 KH500. It's easily the most refined and best handler of the entire series. Kaw spent a lot of money and resources designing the new KH500 frame - the same year the EPA pulled the plug on gas-guzzling, smoking, noisy larger two strokes - the 1975 H2 had a short run of less than 5,000 and the KH500 met it's last run in 1976.
5) H2 - 750 Mach IV. I have 3, one stock 1974, one stock 1975, and one very modified 1974 dragger. I don't like them. They don't have the "hit" the H1's do. Yes, they are faster and they are easier to ride than the H1 around town - gear selection is not as critical. You can pull out of corners at 3,000 easily. It will snatch the front off the ground violently in the first 2-3 gears at 5,000 and above - but where the 500's will spin to 9,000 - the 750 signs off before 8,000. You don't get the howl and the long- wonderful rush of power over 4,000 rpm. The 750 is like a diesel is the way I'd put it - lots of grunt, lots of power - but signs off early. That 500 just gets my juices going.
6) If you plan to modify one to serious power - be forwarned. They quit being fun to ride. I sent my green bike's engine to LRE in NY and have an engine that will make 161hp at the crank - but it does nothing below 6,500 and it's unridable above 7,500 in anything but the top 2 gears and by then you're going stupid fast - so my advice is to leave it alone. I regret it big-time because I can't let anyone ride it and I'm walking a fine line of getting hurt if I do ride. You simply can't get off the gas quick enough or you have tire slip because you can put enough tire in the back - bad move
7) Suk GT750 - what can I say - if you want the Goldwing of two strokes - this is the bike. Water cooled, stone reliable, smooth, power down low - in the middle, up top. It will remind you a CB750 it's that versatile.
** If you are wanting investments - something you can enjoy for 10-15 years and plan to sell them as I do when I get too old to ride - go for the Gamma, H2, H2A,B, and especially the C - it's the most rare of all 750 Kaw triples. These will let you enjoy now and get all of your money back + more later. Don't screw them up and keep the original pieces. Modified bikes normally bring 50% of what the original condition bike will. If it's cut-up and drastically altered - figure it's worthless as an investment. You better frame those as art - it's about all you get.
I hope I've helped. Again, I don't dislike them - I just love my mellow valved 4 strokes more.
Gordon