I'm a big fan of Carlton Kirby from Eurosport. He's sharp as a tack, has some wonderful witticisms, and is often paired with Sean Kelly, whose droll delivery is the perfect foil to Kirby's more animated presence. Kirby's book, Magic Spanner, is a fun read for any fan of bicycle racing. The audiobook is read by Kirby and is a pure delight.
I'm also a fan of Rob Hatch (Eurosport and GCN), Dan Lloyd (GCN), and Matthew Keenan (ABC-Australia and the ASO world English language feed - he's the guy who hosts much of the ad-free Tour de France coverage on NBC Sports Gold).
After many years of Phil Liggett and Paul Sherwen, I grew tired of their same 'ol, same 'ol schtick. Also, as Phil's eyesight started to deteriorate his misidentification of riders grew a bit tiresome to me. Paul Sherwen was a wonderful foil to Phil, and his passing was tragic. If anything, it's forced Phil to raise his game, and pairing him with Bob Roll has worked out quite well. Same thing with Christain Vande Velde, who has come into his own. Paul Burmeister is an affable host, and his hosting duties for NBCSN's "best of" TdF coverage in July was well executed, especially his interviews with current and former UCI pro riders.
Phil Liggett was the first commentator of pro bike racing I can recall. I remember his color commentary for the 1985 and 1986 Tours de France, where John Tesh was the primary host (this was on ABC's Wide World of Sports). I also remember some of the first times when Paul Sherwen co-hosted with his thick East Midlands accent, fresh from the pro circuit (before he learned RP for TV commentary). Their voices are still there in my head, and I'm glad Phil Liggett still hosts, but my heart has moved on.
That said, I'll take Eurosport's coverage any day over the NBC Sports regular network coverage of the Tour de France. I guess it boils down to knowing enough about the sport that the delivery style of Liggett, Roll, Vande Velde, Burmeister, and Schlanger is a bit too simplified for my tastes. Their approach is great for folks just getting into watching pro cycling, but it's not a deep into things as I'd like. NBC (possibly correctly) assumes the average viewer of the NBCSN or full network NBC coverage to have a more casual acquaintance with pro bike racing so there are more rider profiles, basic explanations of things, et al, and while it works for some viewers it's not my cup of tea.
(To wit: I tend to watch the ad-free NBC Sports Gold coverage with Matthew Keenan, then Phil and Bob, so I don't have to hear and see all of the bumper pieces explaining stuff I already know.)
Eurosport's team of Kirby, Kelly, Juan Antonio Flecha, Rob Hatch, Bradley Wiggins, and Greg LeMond is typically more in depth in terms of covering all of the teams (tho they'll sometimes get a little too "fanboy" about Team Ineos with it's deep GB ties, though this seems to be dissipating this season), they tend not to oversimplify their explanations of things, and they assume the viewers have an understanding of the sport to start with.
I'm seeing a similar style with GCN's new Race Pass service, though its coverage in the U.S. is less thorough due to ASO's contract with NBC and other contracts with the like of FuboTV and FloBikes. Methinks they'll have better U.S. coverage for the 2021 season when contracts are renewed. For now, a VPN allows folks to watch the things that are unavailable Stateside. GCN certainly assumes familiarity with the sport.
So if you haven't had the chance to hear Carlton Kirby call a pro bike race, find a way to do so. He's the gold standard for this fan.
Just my $0.02 - YMMV.