I'm not a fan of small cruisers. Have had a few spins on friends over the years and the light weight and rake makes the front end feel hopelessly disconnected. The road models(CG and the likes) are far more capable - read safer!
For much the same reasons I'm fond of sportsbikes. Capable frames with decent suspension and brakes and good modern tyres are in my view safer than road bikes although I'll admit they do egg you on, leaving you more inclined to be travelling quicker - which counters the argument to an extent
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Also worth considering a trail bike. Don't know what it's like round your way but up here a 125 trail bike and a bunch of bungies will get you and your gear to places out of reach to even 4x4s(most forestry gates only block the road so you just ride round it and off you go).
Only problem is when you pass your test you may not want to get rid of it so you wouldn't get any money back to pour into the bigger bike budget.
I'd go along with all this. For a 125 I'd go for a trailie.
Slightly ironcially trailies are really good around town, especially if the roads are undermaintained, also with the upright riding position you get a better view of the road ahead over the roof of the average family car than with sports bikes or cruisers.
It's rare for someone to stick with 125 sports or cruisers for too long, if you want a sports bike and take to biking you'll probably get a bigger one, ditto a cruiser, commuters like the CG and traillies people sometimes do as they have uses in themselves rather than aspiring to something else but being limited because of licensing issues. CGs bullet proof cheap commuting, traillies tend to be comfortable and fun even more so if your a tall bloke, if your somewhat shorter you might want to avoid though.
People I've know who bought 125 cruisers or sports bikes have been very happy with them for the first half year or so ( probably down to the first thrills of biking ) but tended to move larger engines at the first finacial oppertunity after that.
I'd highly recommend sitting on a bike before deciding about buying, other people can advice but what's comfortable for one is not always comfortable for another. Have a chat with a few owners at bike parking zones too, many will probably let you have sit on while stationary so long as you let them know your thinking of getting one and don't ask for the keys.
My own current bike is a Yamaha XJ900 Diversion, more for it's easy mantainence shaft drive 2 up touring and luggage capability than anything else. past bikes old XJ900 wich actually was more comfortable than the Divvy for me, Susuki GS400 fine for sensible motorway run initailly Kawasaki AR125 I learnt on, a slightly larger sports 125 at the time
which I got knowing that when I passed the full test I would derestrict it while saving for something bigger, that reasoning doesn't seem to apply to modern 125s but does to the A2 license after you've passed the 125 (IIRC limited to 33BHP for 2 years.