Fundaah-imho, any piece of land has to have a title deed. If you use that as a starting pt, I think you go further. I've heard people say that if you buy land on certificates, the potential upside is higher once you get the title deed, but I'm don't think (and I stand to be corrected), any bank would lend to you using the certificate as security alone.
In conclusion, unless, you are buying for a short speculative period, go the whole hog and get the deed.
Btw, there are ways of avoiding the bribery cost at Ardhi House.
The Governor of Nyeri - 2017