Strategies for creating 3D text

What are some other strategies for creating 3D text in an efficient manner?

Here's one way, using MeshRegion[] functionality:

RegionProduct[DiscretizeGraphics[Text[Style["Hello", Bold, FontFamily -> "Calibri"]],
                                 _Text, MaxCellMeasure -> 0.1],
              MeshRegion[{{0}, {4}}, Line[{1, 2}]]]

RegionProduct[DiscretizeGraphics[Text[Style["I", FontFamily -> "Source Code Pro"]], _Text, 
                                 MaxCellMeasure -> 0.1],
              MeshRegion[{{0}, {2}}, Line[{1, 2}]]]

With a bit more work, we can take a similar approach to J.M.'s answer to build a water tight model with a base.

text = BoundaryDiscretizeGraphics[Text["Hello"], _Text]

elongate[{a_, b_}] := With[{d = 0.05 (b - a)}, {a - d, b + d}]

full = DiscretizeGraphics[Rectangle @@ Transpose[elongate /@ RegionBounds[text]]]

diff = RegionDifference[full, text]

etext = RegionProduct[RegionBoundary[text], Line[{{0.}, {2.}}]]

final = DiscretizeGraphics @ Show[
  etext,
  RegionProduct[text, Point[{2.}]],
  RegionProduct[diff, Point[{0.}]],
  RegionProduct[full, Point[{-1.}]],
  RegionProduct[RegionBoundary[full], Line[{{-1.}, {0.}}]]
]

The only defects here are misoriented faces (which can be fixed with RepairMesh), but this is indeed a water tight model:

FindMeshDefects[final]

I'm posting a second answer because this method is completely different from my first answer.

Another way to make 3D printable text is with ImageMesh:

hello = Rasterize[Graphics[{Text[Style["Hello", Bold, 60]]}], "Image"];
text = ColorNegate[ImagePad[ImageCrop[hello], 6, White]];

stack = Image3D @ Join[
  ConstantArray[text, 20],
  ConstantArray[ColorConvert[ConstantImage[1, ImageDimensions[text]], "RGB"], 5]
];

ImageMesh[stack, Method -> "DualMarchingCubes"]