I'm using Holtek microcontrollers, family HT46 and HT48, with a good success.
IDE environment is very very comfortable, expecially if you write sources in C.
The IDE environment is provided with no charge by Holtek, so take a look at the holtek website
www.holtek.com
Consider that if you write sources in ASM, you debug in ASM. Writing in C, you debug in C (source level debugging)... this is a great feature, not possible with several other IDE.
Have you looked at microcontroller costs????? I think that there are no cheaper solution than Holtek.
And have you seen how fast is program an holtek micro?
About developing, i don't know what is the politics of your holtek distributor... here, in Italy, the holtek distributor provide me the HT-ICE (in circuit emulator) at NO CHARGE. Instead, I've paid more than 400 Euro for a very weak ICE for philips 87LPC76x !
Regards. Paolo