I like the modern Icoms as they are set up to offer more power on AM and they sound GOOD on AM. I have an original 746 purchased the first year they came out. So the thing I guess is about 10 years old now. Never had a moment's trouble with it. This also coincides with the better beginnings of all the digital componentry and functions.
I used to have an older Icom 751A which was has a famous killer receive section, but it did not sound good on AM. Many or all of the modern ham rigs do not use a typical true AM circuit for transmitting, but utilize a double sideband scheme with a carrier injected to accomplish AM. Apparently Icom changed this at some point....all I can testify to is that my 746 sounds great on AM, and will swing power forward to double of whatever you set the carrier to. They are factory set up to max at 40 watts AM, and will swing to 80 from there. Likewise, if I set it at 20W, it will swing to 40. And that setting can be turned up inside the rig. I've also heard a late model 706 MII G sound great on AM.
The Kenwoods and Yaesus are set up for only 25 watts max, AM and I just don't know if their modern rigs sound good on AM or not. Perhaps some owner-users out there can let us know.
On the Icoms on AM, turn ON the Speech Processor, and increase the Mic Gain only until the modulation peaks hit 100% on the ALC meter. You're good to go.
I use my 746 for all 'round use on HF. Ham, 11 meters, AM, SSB and FM
The 746 and it's big sister, the 746 PRO, have 6 meters + VHF. So after doing the mod, they transmit 1.6~60mhz strait thru, and then again 108~174mhz strait thru. Now's that a darned decent capability.
So IF you're interested in the FT 450 to also be your CB AM rig, you may want to find out for sure if they sound good (have loud-clear audio) on AM. That could be one deciding factor for you. If you definitely want good AM capabilty out of a ham rig, you can't go wrong with any of the modern Icoms. Hope any of this info is useful to you and good luck with whatever you choose!