The only thing you’d lose would be the varibrightness, which others comment on as being particularly useful on the trilogy.
At this point, I’m tempted to link to Thom Hogan’s Advice On Buying Tripods, and in particular, Maxim #2, in which he suggests you spend a lot of money on a tripod, or alternatively, you could spend even more money buying the same tripod.
To whit: if you save, say, about $300 on buying a varibright 128, and then decide you actually really do want the varibright, and you pick one of those up, go through the hassle of selling the old grid, perhaps lose money in the process, and in the end spend way more on the thing you were planning on getting anyway.
You’re lucky in that due to the nature of the monome community, they hold their value and have decent resale potential, but it seems like robbing Peter to pay Paul; I’d rather go slower on acquiring modules - maybe park a less essential module for later, and plump for an alu 128. (he says, not owning any monome gear himself).
