I am coming from a female perspective and not a long time rider who has ridden/owned a ton of bike.
I started with a Gixxer 600 2009 as my first bike in Jan 2011. Love the bike for what it is..a super fast sport bike. I was definitely a bit intimidated by this bike at first, timid...but now..2 years later..that sexy girl is my dedicated track bike and have since bought a 2009 gixxer 750 as my "new to me" street only bike.
So...the Bonnie....sigghhh...she was a "lust" purchase back in June 2011. Again..I am not a bike expert...but I was driving upvalley in Napa one afternoon and saw this gal riding a Bonnie..she looked as cool as a cucumber on that bike...she looked like that bike was made for her..easy riding! I thought at that moment..."I want to feel like she looks"! I HAVE to at least sit on one. So I went about a month later to a local Triumph dealer and sat on the base model 2011. I FELT like that girl looked! The dealer's shop model for test riding was not working at the time so I didn't test ride it. After more research..I just went to another dealer and bought the SE model..2011.
Perhaps being the Gemini that I am with two personalities..my Gixxer and my Bonnie are very different bikes for very different riding experiences. The gixxer is my "devil" and the bonnie is my "angel". I feel totally different on both bikes..old school "Fonzi", Steve McQueen..whatever..on that bonnie and crazy a$$ motoGP(at least in my head) on the Gixxer! When I want to chill out for an easy going ride, I will take out my Bonnie. The SE has the 17" rims (T100 has 19") so she is very nimble in the twisties in a very easy going way. I won't be doing any knee dragging in the twisties on her, but she can handle them just as well as the gixxer can. Some folks who see me ride her say I always look more at ease on her in the twisties..but it really is just how you sit and handle that bike. She is easy and fun!
As for slab rides...yeah...pretty comfy but her top speed really is about 85mph..probably most happy just cruising around 75ish. She's a kitten..just purrs...My friend and I both changed out the sprockets to add a little more "oomph" to the top end..not much..but enough to make it noticable. We both rode our Bonnies to Oregon and back..I did 400+ miles of slab alone on the way back with only a few short breaks and the only pain I had was my throttle wrist..should have used the little cruise control lock I had..but it was not bad.
You DO have to change your seat. I had it reupulstered slightly to add memory foam. the stock seat is rock hard. The sacrificed foam and padding for a lower seat height. My friend actually had 3-4 inches or more to make it taller because he is taller and it works better for him. he has the T100 which sits slightly higher anyway because of the bigger wheels.
Suspension sucks on the bike. My friend changed out to Ohlins...I still have stock..there is very little adjustability to it..and at some point may change..but I made it all the way to OR and back on stock and was no worse for wear on nice roads...just don't expect it will handle lumpy bumpy roads well.
All in all..she is a very fun little bike. My work horse bike..I can put saddle bags on her, pile stuff on the back luggage rack and carry lots of stuff if I need to. I don't always need to be going 100mph+ so "slowing" down to her top speed is okay..she is nimble in twisties and comfy on long rides.
I REALLY would have loved to have teh Thruxton as I love cafe racers..but feel THAT bike is underpowered for being what it is..more of a racer type bike. the tech specs exactly match a bonnie amazingly...so that bike I would want to soup up..I could thruxtonize the bonnie at some point..but then it would be more like the gixxer in feel..race pegs, clip ons..etc...BUT then I would lose my "old school" fonzi coolness of teh Bonnie. People always think my "modern classic" is older than it is...get lots of old geezers coming up telling me stories of their "college sweethearts" back in the day!!
Anyway..long answer...but the Bonnie is what it is..it will never be a sport bike..doesn't even pretend to be..if you want that cruiser style without it being a Harley lazy-boy type experience..this bike is just fun..souped up or not!!!
Cheerio!