I haven't yet heard the Quilter Bass Block and I
would like to play through one to check it out. But a couple of sentences regarding size, weight, and bulkiness are somewhat misleading here.
From the Quilter Bass Block Specs page on their website:
Dimensions:
H x W x D 8.5”(218mm) x 7.5” (190mm) x 3” (76mm)
Weight:
3.7 lbs (2kg)
From the TecAmp site Puma 900 Specs page on their website:
Dimensions
Width 10.7 in
Height 1.6 in
Depth 8.3 in
Weight 2.4 lbs
The Puma 900 weighs less and is very comparable dimensionally to the Bass Block so based on this, I wouldn't call it "bulky" comparitively speaking.
I
have played through a GK MB500/MB00 and although they sound good, IMO they don't sound/feel as great as the Puma 500/900. In the end, it's so subjective that 5 out of 10 players may prefer one as opposed to the other if compared side by side. Once again, I have yet to play through a Bass Block and would like to at some point to check it out.