Maximum number of user for DHCP/DNS services

Hello everyone, I would like a recommendation for best device for VLANS, DHCP and DNS services for a mini network setup for approximately 150 users. The device will not do wireless, being taking care of by other devices.

DHCP to serve 4 VLANS and DNS for simple DNS filtering using a blacklist via dnsmasq and DNS request Logs.

somebody suggested me the xiaomi midwifi 3G but to me the part DNS filtering using a blacklist via dnsmasq and DNS request Logs might consume more CPU than what is inside this little device.

By which he stated that dedicated device for such use from other vendors are using same processors with less RAM.

Any suggestion/recommendations from you people are most welcome.

thank you