Add New Insteon or X10 Switches to existing X10 installation?

[Mitch <sumcoolgai@xxxxxxxxx>]

I've got about 70 X10 receivers (dimmers, switches, appliance modules
and lamp modules) in my house today.  Almost all of these are Smarthome
(some are Leviton).

I need to add about a dozen or so new modules (some inline modules, new
lamp modules, appliance modules, relays and dimmers).

My question is: should I stick with X10 modules or go with the Insteon
modules?

I have no immediate plans to switch to Insteon, but I'm wondering if it
is wise to get them to give me this option in the future.

I'm also concerned with signal attenuation.  It's my understanding that
the Insteon modules suck signal the way the 2-way modules do (but I will
probably add a few 2-way X10 modules anyway).

Thanks for any inputs you have!

Mitch