The are close. Have travelled with 5Stars and Transtars. Many of their counter staff are from Malaysia. Since they are budget companies, you can expect most of them to be pretty rude.

They are located very near to one another. Be sure to shop around for a better price for the iternerary that you want.

I think the Travel Fair is in Feb? Maybe you can book your tour there then. Cheaper and often with free gifts.

If from Singapore, Transtar & Grassland are among the popular ones in Singapore..

However, if you are looking for agents that based in Malaysia..i suggest you should go for -

Holiday Tours

Sri Sutra Travel

Triways

or the most recommended will be by Mayflowers

if that is a singapore travel agency..its better you post the question to singapore section.
hmm by the way in malaysia the popular travel agency is Reliance and Mayflower,

sorry laaa we Msian don’t use any tour agency to travel in our own country