I've used the chaintool with assembler/emulator/programmator for the Zilog familly Z86 (Z86E04, 08 & 40) there is 6 years ago. It was cheap, useful, but these microcontrollers aren't powerful as 89c668 for example. As it was in a compagny I've worked in the past, I didn't kept these chaintool at home.

Then I've used an old in-line IAR C compiler for 68HC11 (V3.30 from 1993). The reason why I didn't continued with this compiler is that this was dedicated for HC11 and I hadn't the compiler for 8051.

This compiler was terrible.
In order to include asm command in the C source file, it was necessary to write opcodes !

example :
{
_opc (0x4F); /* CLRA */
_opc (0x7E); _opc (0x20); _opc (0x00);/* JMP $2000 */
}

The reason why I've abandoned the 68HC11 is that it's expensive, no longer produced and with limited features.

For evaluation of current chaintools, I've downloaded the demo version of the latest chaintool from IAR system, ImageCraft, Keil.
I haven't tried the Raisonance one.

For the basic features, I think that all are including the minimum required features. I'm not a so good programmer in order to evaluate the advanced features. I let do this to my team.
Personnaly I don't want to use the uVision 1 IDE which is as you said too limited fror own applications. That's why I'm trying to understand the in-line controls in order to use the Keil C compiler 5.50 and the linker 3.70 with batch files. For IDE I'm using UltraEdit32 which is really good.

Stephane