I got an I-Mate Jasjar, bought it second hand so it's about a year old now.
My experience so far has been great.
I use it as my primary phone at the moment, so only complaint is it being somewhat bulky..but then again the screen is full VGA [640x480] and great to work on...can't get that on a smaller phone.
The Jasjar is missing EDGE...i still can't fathom why they missed that, wouldve been useful with my Virgin Sim. It got 3G though, so that makes up for it somewhat.
Battery life, i don't know what is "bad". I get 5 hours from it on FULL LOAD [that is 3G/WIFI going full blown + playing MP3s/Movies etc] , this already beats my laptop's battery power by 2-3 hours...
On "SLEEP" mode it easily goes 3 days, if not more. I didn't test this to the limits as it charges via USB..so everytime i sync it charges anyway.
You can buy the Jasjar/I-mate stuff at Leaf
www.leaf.co.za. Their shops are in Sandton.
As for reception, i haven't had noticable issues with that. I don't always get a good 3G "lock" and it will jump between 3G/GPRS endlessly. Luckily you can set it to go 3G-Only or GPRS-Only.
Oh, as for K-Jam [or similar phone variety] vs. Jasjar . Things to consider. Jasjar got a 530Mhz CPU vs. 200Mhz CPU on the K-Jam. Screen is also QVGA vs VGA . I think even the upcoming Jasjam will only have a 400Mhz CPU .... Makes a huge diff if you got a fast CPU + full VGA , especially when you start remote connecting to desktop pcs or playing divX movies.
PS: I update my Jasjar's firmware/OS/ROM [whatever it's all called] to the latest one, alot of fixes went in with that too in terms of the OS functionality etc . Not sure what the main bugs were with the Jasjar when it came out, i haven't found any show stopping things and i am pushing mine to some limits [i.e. i am running PocketDOS/Emulators on it with various DOS/ROMS being run inside the emulator...a few people actually managed to install Windows 95 inside PocketDOS etc..]
PSS:
This took me awhile to sort figure out. The Pocket PC got 3 modes : The "Active" , "Sleep" and "Only Backlight turned off" . There is a HUGE difference between "Sleep" and "Only Backlight off" modes in terms of battery power.
Basically in sleep mode the ppc turns its CPU off [same as windows] and certain events "wakes" it up again [incoming calls]. The wake-up process obviously takes a few secs etc. You can turn this mode off and the ppc will work the same as most cellphones where only the backlight turns off.
Anyway long story short: I made the mistake of putting my ringtones on my SD card , and it takes the PPC 3-6 seconds to initialise the SD storage when it "Wakes" . End result : My phone took 6 seconds to start ringing [playing the ringtone] on an incoming call ...even though technically it was ringing much longer than that.
So i turned off the sleep mode and walked around with it just turning the backlight off...i didn't get more than a day out of it that way.
I never thought I was ever going to say this.